Neuroblastoma mets to brain
12-14 mths after initial Dx . Solid or cystic.
Can enhance, hemorrhage, calcify.
Can involve leptomeninges
Higher risk with
bone marrow involvement,
LP at dignosis,
Young age 2-3.
Lymphoma mets to brain
Brain and abdomen involvement is very rare
Differential of restricted diffusion
CNS complications in ALL
Methotrexate CNS complications
Intrathecal or systemic
No specific age group
Restricted diffusion resolves whith symptoms
Hemiparesis and aphasia most common
Long term leukoencephalopathy.
Cord herniates through dura.
Typically ventral and midthoracic.
Brown-Sequard is most common symptomotology
Can be idiopathic, iatrogenic, traumatic.
MRI best, then CT myelo to differentiate from arachnoid cyst.
Treat by surgery with reduction-some improvement even in chronic cases.
Carotid artery dissection
Often overlooked cause of ant. circ. infarcts
Peak at 50s. Healthy individuals.
Prediposition from hypertension, Ehlers-Danlos disease, Marfan syndrome, fibromuscular dysplasia, migraine, oral contraceptives, and pharyngeal infections.
Often a history of minor trauma (chiropractic, yoga, ceiling painting, nose blowing, judo, coughing, sneezing, vomiting)
Often a mural hematoma, so no flap seen, no contrast in false lumen.
Use fata-sat to highlight methemoglobin in hematoma.
Treat with anticoags and aspirin.
Capillary malformation with normal surrounding brain tissue.
Occult on angiography because of small vessel size and slow flow.
Have no Ca, Gliosis, hemorrhage and so do not show up on FLAIR, T1, T2
Best visualized with Gad and susceptibility imaging on MR
Most are asymptomatic
Most common location is Pons, midbrain.
Most common primary ocular malignancy adult
Rare in children.
Characteristic collar button configuration tif erupts through Bruch's membrane
Solid well defined,
Variable MRI appearance depending on melanin content. Moderate enhancing.
Highly vascular hypoechoic on US.
Can happen in any section, Iris, ciliary body, choroid.
Mets hematogenously to liver, lung, bone, kidney, and brain in that order.
>10mm enucleate. 3-10mm radiation and brachytherapy. <3 mm may be benign nevi, so monitor and biopsy.
Results from splitting of meninges and then trapping of CSF inside the new space.
Most common location is middle cranial fossa.
Follows CSF signal on all signal (suppresses on FLAIR, unlike epidermoid)
Usually asymtomatic, but can cause symptoms by mass effect.
Polyneuropathy, Organomegaly, Endocrinopathy or Edema, M-protein and Skin abnormalities (hyperpig)
AKA Crow-***ase syndrome, Takatsuki disease, or PEP syndrome
Combination of a plasma-cell proliferative disorder (typically myeloma), polyneuropathy, and effects on many other organ systems.
Average age at onset is 50 2:1 M:F
Polyneuropathy is usually symmetrical and distal
Demyelination and axonal damage, sensory, motor
autonomic neurones are all affected
Endocrinopathy: In women, amenorrhoea, and in men,
gynaecomastia, erectile dysfunction and testicular atrophy
M-protein=monoclonal IgG or IgA, in 75-80%
Skin changes, lots of variations. Clubbing.
Well defined cyst in pineal region
Usually <1cm and asymptomatic
3:1 F:M most commonly diagnosed in 30s.
Expansion very rare.
>10mm needs follow-up as can sometime enlarge
Symptoms from mass effect-aqueduct compresstion
Can rim enhance, look for thin even rim. Thick/nodudlar=pineocytoma
Hemorrhage may result in rapid expansion=pineal apoplexy
Follows proteinaceous fluid characteristics. Variable
depending on exact content.
Contrast may eventually diffuse in, so beware late imaging
Germ cell tumor
Warthin tumor arises in incorporated lymphoid tissue.
60 years mean age at presentation
Malignant transformation in <1%
Recurrent likely from incomplete resection
Smoking (90% of tumor presentation in smokers)
Multiple lesions or bilateral, think Epstein-Barr virus.
PEARL - Sharply demarcated round/oval mass with
profound intraparenchymal inhomogeneity
Most are intraparotid within the parotid tail
2-4 cm in diameter
Minimal enhancement of solid component
PEARL - MR with contrast best for determining location
T1 - Hypo intense in both solid and cystic component
T2 - INTERMED->Hyper intense in solid component and
hyper in cystic component
T1 C+ - Minimal enhancement of solid component
Anechoic mass with inhomogeneous pattern
2nd most common benign parotid gland tumor
20% multicentric, unilateral or bilateral, synchronous or
5-10% in upper neck or peri-parotid
Subependymal giant cell tumor
WHO grade 1 tumor occurs in 15% of Tuberous sclerosis
Present with mass effect (headache, vomiting, obtundation) due to foramen of Monro obstruction and hydrocephalus.
Mean age is 11 years
Seeding is rare
Survey until resection is necessary
Iso to gray matter on T1
Hyper to gray on T2 and FLAIR
Calcium may lead to hypointensity (hyperdense on CT)
Pretty much impossible to differentiate from subependymal nodule.
Rare, only 1% of Ewing carcinomas
More often involves frontal and parietal bones.
Onion skin appearance less likely (as opposed to long bones)
Diffuse permeative destruction of inner AND outer table (as opposed to Histio X which has differential destruction)
Large, avidly enhancing complex extradural mass.
Well differentiated, heterogeneous appearing.
Cystic degeneration common, hemorrhage is not
Mostly frontal cortex, rare in ventricles and cerebellum, even more rare in stem and cord
Peak incidence 4-5th decades.
Most common symtoms Seizure and Headache
Resection is tratment of choice.
Upward protrusion of the odontoid process into the infratentorial space more than 3 mm above Chamberlain's line 4.5 mm above McGregor's line.
Also associated with syringohydromyelia, atlas occipitalization,
Called Basilar Impression when acquired
Upper cervical cord comression syndrome (labile BP, Arrhythmias)
Posterior skull pain
Treatment is surgical, though some asymptomatic patients can be treated conservatively.
•Slow-growing tumor arising from the ependymal cells of the filum terminale.
•Occurs almost exclusively in conus medullaris, filum terminale, and cauda equina.
•13% of all spinal ependymomas
•More common in males (M:F=2:1) with a
•Mean age of 35 at diagnosis
•Does have drop mets, but not as frequently as other types.
occasionally bowel and bladder dysfunction
•Typical imaging features
markedly enhancing intradural tumor with
heterogeneity due to hemorrhage,
calcification and cysts.
Span two to four vertebral segments, and
Well-circumscribed intradural masses.
T1 isointensity, T2 hyperintensity, and
Avid enhancement on post-contrast images.
• Surgical resection usually curative.
• Rads and chemo for mets.
NAA NMR peak
Low in neoplasms that destroy neurons and demyeliniation
Creatinine NMR peak
Choline NMR peak
High in neoplasms and demyelinating disease due to cell membrane turnover
Lateral corticospinal tract
Motor to contralateral muscles
Motor cortex-coronoa radiata-post limb int capsule-cerebral peduncle-medulla decussation-posterolatera cord.
Anterior corticospinal tract
Motor to ipsilateral muscles
Primary cortex-corona-posterior int caps-peduncle-central pons-medulla no decussation-anterior funiculus and ant column of cord.
Motor to contralateral limbs
Red nucl-Decussation in ventral tegmentum-Lateral funiculus-posterolateral cord white matter lateral to corticospinal tract
Automatic movements (strethc, walk, head coordination)
Pons-medulla-ipsilateral anterior column in cord.
Balance, posture, head coordination
Touch and limb position
Posterior WM-medulla dorsal nuclei-decussation-medial lemniscus-thalamus-anterior capsule-primary sens cortex
Pain and temperature
Dorsal horn-spinal decussation-anterolateral spinal tract-pons reticular formation-medulla-thalamus
Auditory in caudal pons-crossed and uncrossed to inferior colliculus-medial geniculate-priomary aud cortex.
Optic tract lesions
nerve-all vision from ipsilateral eye
optic chiasm-bitemporal hemianopsia
tract- contralateral field defect (all right or all left)
radiation-various contralateral regions-Superior radiation in parietal lobe=lower visual field, inferior fibers (meyer's loop) anteroinferior to lat ventricle=upper field.
Visual cortex-entire contralateral field except fovea.
Origins of vranial nerves
1-4 from mmidbrain
5-8 from pons
9-12 from medulla
III nucl just posterior to red nucl.
Passes PCOM, susceptible PCOM aneurysms.
To orbit through sup. orbital fissure.
Edinger -Wesphal nucleus controls nucleus.
Nucl in midbrain just below that of 3rd CN
Contralateral interconnections in meidal longitudinal lemniscus.
Unique posterior exit and complete crossover.
To orbit through sup fissure.
Supplies superior oblique.
Nucleus medial to middle cerebellar peduncle.
Exits laterally, synapses in Meckel's cave gasserian ganglion, then trifurcates.
V1, ophthalmic, runs inferiorly in cavernous sinus, enters in superior fissure. Supplies upper face, lacrimal gland, eye, nose.
V2 goes through foramen rotundum, runs in pterygopalatine fossa. Supplies maxillofacial region. Maxillary nerve branch goes into inferior fissure.
V3 Mandibular, supplies mastication muscles motor, lower face, ear sensory, TMJ, tympanic membrane.
Trifurcates to auriculotemporal, lingual and inferior alveolar nerves.
Nucleus in middle of pons near floor of 4th ventricle.
Leaves anteriorly at junction of pons and pyramids. Goes through Dorello's canal, then cavernous sinus, where it is susceptible to compression by carotid.
Nucleus in midpons anterolateral to abducens.
Fibers circle abducens nucleus before exiting anteriorly. Crosses cerebellopontine angle cystern then into auditory canal (anterior superior).
Nucelui in superior medulla at base of inferior cerebellar peduncle. Cochlear division runs anterior inferior in auditory canal. Vestibular branches run posterior.
Nucleus in medulla posterior in inf olivary nucleus. Nucleus ambiguus for motor (shared with vagus), inferior salivary for spitting tractus solitarius for taste.
Fibers pass through olivary sulcus, pars nervosa of jugular foramen, through superior constrictor muscles. Innervate pharynx and stylopharyngeus muscles. Posterior 3rd of tongue. Supplies Jacobson's nerve among others.
nuclei in medulla, nucleus ambiguus (shared with IX), Dorsal nucleus (just anterior to 4th ventricle), Nucleus solitarius. Exits medulla through olivary sulcus, out through pars vascularis of jugular foramen, runs in carotid sheath where it is susceptible to compression.
Fibers from first 3 cervical levels and motor cortex. These make ansa cervicalis which runs up along carotid sheath then out jugular foramen. Supplies infrahyoid strap muscles, sternocleidomastoid, trapesius.
Nucleus in paramedian area of 4th ventricle anteriro wall in medulla.
Exit anteriorly in preolivary sulcus. Goes through hypoglossal canal Supplies intrinsics of tongue, genioglossus, styloglossus and hyoglossus.
Branches of ECA
In anterior to posterior order, numbers are by prox to distal
1 Superior thyroid
7 Superficial temporal frontal and parietal
6 Posterior auricular
3 Ascending pharyngeal
Persistent trigeminal artery
Origin from cavernous carotid. Feeds top of basillar. Runs in suprasellar cystern. Prone to aneurysms.
Persistent Otic artery
Origin from petrous carotid. Feeds mid basilar. Runs in internal auditory canal.
Persistent hypoglossal artery
From high cervical ICA at skull base. Feeds intracranial vertebrobasilar. Runs in hypoglossal canal.
Persistent proatlantal type 1 artery
Origin at low ICA. Feeds cranial and cervical vertebrobasilar. Runs at C2 level.
Persistent Proatlantal type 2 artery
Origin from external carotid. Feeds same as type 1
Associated with hypoplastic vertebral arteries.
Branches of vertebral arteries
Anterior spinal, supplies most of the cord.
First branch in intracranial compartment is the PICA
Basilar artery branches
Terminates as the two PCAs most of the time.
Contents: Olfactory nerves.
Contents: Optic nerve, Ophthalmic artery
Diseases: Optic nerve gliomas, meningniomas
Superior orbital fissure
Contents: Oculomotor, trochelar, abducens, V1. Ophthalmic veins, sympathetic nerve plexus, small arteries
Contents :Maxillary (V2)
Diseases: Schwannomas, Meningiomas, PNS
Contents: Mandibular (V3), lesser petrosal nerve, small arteries, emissary veins.
Diseases: Schwannomas, Meningiomas, PNS
Contents: Facial nerve, stylomastoid artery
Diseases: PNS, Bell's palsy, schwannoma
Internal auditory canal
Contents: CN VII and VIII, labyrinthine artery
Diseases: Schwannomas, meningiomas, epidermoids, archnoid cysts.
Jugular pars nervosa
Contents: CN IX, inferior petrosal sinus
Diseases: Schwannoms, meningiomas, PNS
Jugular pars vscularis
Contents: CN X, CN X1, IJ, small arteries.
Diseases: Glomus tumors, Schwannomas, meningiomas, PNS, mets.
Contents: CN XII, emissary vein, small arteries (persistent hypoglossal artery, when it is present at all)
Large glomus jugulare
Neurotropic spread of tumor
Contents: Spinal cord, vertebral arteries, spinal arteries and nerves
Diseases: Meningniomas, chordomas, schwnnomas.
Contents: Middle meningeal artery/vein, meningeal V3 branch, lesser superficial petrosal nerve.
Contents: Carotid artery and vidian nerve cross over it. Greater petrosal nerve.
Contents: Nasopalatine nerve, palatine arteries
Greater palatine canal
Contents: Greater palatine nerve, palatine vessels
Contents: ICA, sympathetic plexus.
Foramen of Vesalius
Inconstant emissary foramen anterior and medial to foramen ovale.
Contents: Emissary veins
Contents: Lesser petrosla nerve
Contents: Emissary vein
Contents: Endollymphatic duct, meningeal branch of occipital artery
Diseases: Meniere's disease, congenital stenosis, patulousness
Contents: Emissary vein, meningeal branch of occipital artery
Contents: Emissary vein, meningeal branch of occipital artery
Contents: Pharyngeal branches of pterygopalatine ganglion and maxillary artery
Contents: Perilymphatic duct, emissary vein
Diseases: Congenital stenosis or patulousness
Inferior orbital fissure
Contents:Maxillary nerve, zygomatic nerve, orbital pterigopalatine branches, infraorbital vessels, inferior ophthalmic veins
Diseases: PNS, Schwannomas
Contents: Infraorbital nerve and vessels
Diseases: blow-out fractures
Contents: Mental nerve and vessels
Diseases: Squamous cell carcinoma
Contents: Inferior alveolar nerve and vessels
Diseases: Schwannomas, Squamous cell carcinoma
Contents: Maxillary artery, Maxillary nerve, sphenopalatine veins
Diseases: Juvenile andiofibromas
Contents: Vidian nerve and artery
Meningothelial origin tumors
Mesenchimal origin tumors
Solitary fibrous tumor
Malignant fibrous histiiocytoma
Melanocytic origin tumors
Tumor of meningeal origin
Frequent imaging findings
Adjacent ostolysis or hyperostosis
Obtuse angle with dura
Calcification about 20%
Alanine peak on MRS
Hyperdense on CT
Cysts, Hemorrhage, Axt into auditory canal are rare.
Skull base meningiomas may require embolization prior to resection
May encase and comress adjacent vessels.
Atypical type is WHO grade II. By pathology only, imaging is identical.
Malignant type is WHO grade III, rare, diagnosed by atypical behavior (rapid expansion, intraparenchymal ingrowth)
Rad induced type is most common rads induced tumor. About 35 year latency mean.
Tumor of Schwann cell origin
Frequent imaging findings
Acute angle with dura
Cysts in about 10%
Often inhomogeneous enhancement
Often extends into auditory canal
Taurine and/or GABA peak on MRS
Isodense on CT
Dural tail, Bony reaction, Calcification, hemorrhage are rare.
Meningeal mesenchymal tumor deriving from smooth muscle pericyte cells.
More agressive than most meningiomas with higher recurrence.
Mostly large, over 4 cm,
Hyperostosis or coacification is rare.
Associated with NF II
Usually in cortex, but about 10% are meningeal
May present with seizure in young pt.
All look alike on imaging, path necessary for diagnosis.
Antoni A cells presominate
Likes CN V VI pelvis, retroperitoneum, mediastinum
Found in skin, subcutaneous soft tissues
associated with NF 2
Like spinal nerves over cranial.
Cerbellopontine angle masses
Vestibular schwannoma (75%)
Facial nerve schwannoma (4%)
Vert, basilar, posterior, PICA
Brain stem glioma
Subarachnoid spread of tumor
Choroid plexus papilloma
Specifically associated with NF 1
Mostly in skin and subcutaneous soft tissues (the skin tags)
Contain mixed cells, schwann, perineural, fibroblasts etc.
Antoni A or B can predominate.
Plexiform type can occur (again, NF 1)
Post-traumatic proliferation of nerve cells. Not a real tumor.
No perinueral lining or fibroblastic tissue.
Can occur after nerve avulsion (C-spine)
Look like small schwannomas on imaging.
Chunky thickening of dura on imaging.
Can even spread on top of meningioma.
Most common locations for SAS
Cerebellopontine cystern along CNs
Tumor of immature granulocytes associated with myelogenous leukemias.
Can occur anywhere, often predates the leukemia.
Orbit and epidural space most common in CNS
Prominent vasogenic edema
Choroid plexus papilloma
What it says. WHO I
Most present before 5 years. up to 20% in 1st year.
In children 90% are in lateral ventricle antrum.
In adults most are in 4th ventricle.
Overall lateral, 4th, 3rd, ceerebellopontine angle.
SV40 virus implicated.
Presents with hydrocephalus and papilladema by CSF overproduction or obstruction.
Can be present a foramen of luschka (extension)
Low T1, mixed T2. Enhance dramatically. Flow voids.
100% survival at 5 years for complete resection.
Choroid plexus carcinoma
WHO grade III
Rare compared to papillomas. About 10-20% degen. rate.
Lateral ventricles predominantly.
CSF dissemination in 60%
Can't really distinguish from benign papillma on imaging. Look for parenchymal invasion
40% survival at 5 years even with complete resection.
Choroid Plexus hemangioma
Usually in lateral ventricle
Some association with Sturge-Weber syndrome (often ipsilateral to vascular malformation in this case)
Choroid plexus xanthogranuloma
Centered on glomus in lateral ventricle
May have fat density in it.
Often bright on DWI
Choroid plexus neoplasms
Epidermoid CNS cyst
Arise from rest of epidermoid tissue resulting in collection of keartin, cholesterin epithelium debris (white cheesy stuff)
Peak incidence 20 to 40
Most often in
cerebellopontine cystern (trigeminal neuralgia, facial paralysis)
Extradural much less common tha intradural in which case
Weel defined bony lesion with sclerotic margins
Low density, but not fat
No bone or calcification
Expand to fill available spaces
Typically do not enhance, but may have a bit of wall enhancement.
T1 hypo, T2 hyper like water, but Bright on FLAIR
Usually very bright on DWI
Arises from rest of dermoid cyst.
May have hair follicles, sebacious glands etc.
For that reason has high fat signal and calcifies
Typically in midline as opposed to epidermoids.
Younger and more male patient set
Look for phase shift on MRI to prove fat.
Can rupture causing multiple fat droplets all over.
Rests of all three tissue layers.
Pineal and suprasellar cysterns most common locations
Mixed density or intensity lesion. Often gross fat present.
Look for peripheral enhancing nodule to differentiate from dermoid (not a sure thing)
Not true neoplasm.
Associated with agenesis of corpus callosum
60% association with a congenital anomaly of neural elements
Most common sites
Quadrageminal plate cystern
Look for entirely fat signal and fat suppression on MR
Juvenile pilocytic astrocytoma
Most common juvenile infratentorial brain tumor. 60% in posterior fossa, but also like optic pathways and hypothalamus.
WHO grade I
Usually well defined, round.
Cystic with a mural nodule is classic, but may be solid.
Hypo T1, Hyper T2/FLAIR
Cystic portion follows CSF characteristics.
Solid portion enhances strongly
Compare to fibirillary astrocytomas: Less invasive, better prognosis, younger children. Also more frequent 85% vs 15%
When at hypothalamic-optic chiasm-3rd ventricle region, associated with NF (type ?)
Brain stem glioma
Infiltrates the brain stem and therefore can not be excised.
80% occur in childhood and comprise 20% of posterior fossa tumors.
Treatment is radiation.
WHO grade II, 25% survival at 10 years.
Pons is most common.
There is a tectal and exophytic type, with better prognosis.
MR is best
About a third enhance.
Comprise about 1/3 of posterior fossa t umors, 50% of cerebellar tumors.
Very malignant, WHO grade IV
Usually midline from vermis then growing upwards in kids.
More often lateral in cerebellum in older patients.
Typical age range is 5-12, m>f
Typically presents with hydrocephalus
Associated with Turcot's syndrome and Gorlin's syndrome
Melanotic type has worse prognosis.
High seeding rate
Homogeneous hyperdense (as compared to ependymoma)
Displaces 4th ventricle inferiorly
Can have cystic change
Hypo T1, iso T2
Not much edema
Can seed (sugarcoating) up to 50%
Low NAA:Cho ratio. Usually not lactate
Look like regular medullablastoma. Myogenic features on histology.
WHO grade IV, death within 1 year.
Highly agressive, heterogeneous, often hemorrhagic, necrotic, calcifications and cystic change.
Dense on CT, patchy enhancement
ABout 1/3 have subarachnoid dissemination.
About half in posterior fossa. 40% supratentorial, 5% peripheral. Multifocal or spinal is rare.
Cellular: WHO II, Peaks 0-9 and 30-50 (spinal)
Papillary: WHO II, Peak 0-9
Clear cell: WHO II, 0-9
Tanycytic, WHO II, 30-50
Anaplastic: WHO III, 0-9
Myxopapillary: WHO I, 30-40
Subependymoma, WHO I, 40-60
Usually 4th ventricle when in posterior fossa. (can hang out of foramina)
About 20% intraparenchymal
Prognosis varies by site
Filum terminale best (WHO I)
Posterior fossa worst (WHO II)
About half calcify (typically punctate)
Hypo to isodense
CLASSIC: Calcified mass in 4th ventricle extending through Luschka and Magendie.
Hypo T1, Intermediate T2
Can have hemorrhage.
Hypointensity may reflect calcification
High rate of seeding.
WHO grade 1
Look like ependymoma in every way except location.
Most common location (lateral recess of 4th ventricle, then lateral ventricle and septum pellucidum
Lateral ventricular arise later in life (>15 or so)
Most do not enhance.
Isodense on CT and isointense on MRI
Mean age 51
Gross fat can be seen.
Otherwise look like medulloblastomas.
Most common primary intraparenchymal tumor in infratentorial space in adults. Pretty much the same lesion as JPA in children. Differentiate mostly by pt age.
WHO grade I, cured by resection.
83% in cerebellum, remainder is sp cord, medulla and cerebrum.
Much rarer than schwannomas and mets.
Young adults, M>F
Commonly present with headache, ataxia, nausea, vomiting, vertigo.
Ofter has polycythemia due to increased erythropoietin
25% associated with vHL
Typically cystic mass with solid mural nodule (60%)
Highly vscular-serpentine signal voids
Can be solid or purely cystic. Solid ones enhance avidly.
Manifestations of vHL
Islet cell tumor
Endolymphatic cell tumor
Most common neoplasm in brain overall.
Usually well defined with a lot of edema. Mostly near G/W junction.
Most are low density excepting calcifications, hemorrhage, proteinacious material
Variable appearance of T1 and T2
Hemorrhagic CNS mets
Calcified CNS mets
Calcified CNS primary tumors
Choroid plexus papilloma
Any post radiotherapy.
Features of bleed from occult cavernoma
Edema only early on, resolves by 8 weeks
Complete hemosiderin ring
No soft tissue component
Minimal enhancing centrally
Classic hemorrhagic progression on MRI
Decreases in size on f/u
about 1/5 calcify
Features of recently bled mass
Persistent edema on f/u
Persistent mass on f/u
Hemosiderin ring incmplete or absent
Soft tissue component
Nodular, ring, eccentric enhancement
MRI progression delayed
Increased in size on f/u instead of decreasing
Children and young adults (first three decades)
Preference for peripheral temporal lobes
Meningeal base in 2/3 cases
Often present with seizures (think to the location)
Cysts in 1/3 to 1/2
Hemorrhage and calcification uncommon.
No cortical dysplasia
WHO grade II 80% at 5 years.
Similar to DNET on imaging.
Supratemtorial PNET formerly cerebral neuroblastomas
WHO grate IV
The younger at diagnosis, the worse.
Often cystic 1/2 to 2/3, hemorrhagic, pediatric
High recurrence and seeding rate
Usually large at diagnosis
Heterogeneous and heterogeneously enhancing on CT and MRI
Not much edema
WHO grade IV
Occur in infants
More supratentorial, but can in infra
Temporal more than parietal, even in globe
With progression develop pretty much any appearance, cysts, calcification, necrosis, enhancement, eventually subarachnoid dissemination
WHO grade IV Death 6-12 months.
Neonates and young children.
Supratentorial as opposed to ependymoma
Large at diagnosis with enhancement, edema, peripheral necrosis, cysts
Still pretty well circumscribed.
Arise in periventricular neuroepithelium, so usually appose ventricles.
Children and young adults (80%<30 years) F>M
Most common mixed glioneural tumor in CNS
Usually present with seizure
Benign, Slow, Bony remodeling
Temporal (up to 85%)
Anterior 3rd ventricle
Often cystic (more in younger pts), hypodense
MRI features vary depending on cyst composition
Worse prognosis with higher metabolism on PET, vasogenic edema, degree of glial differentiation
No actual glial component, so no potential for malignancy unlike gangligliomas.
Cerebral cortex or cerebellum (what's left)
Can be called Lhermite-Duclos if cerebellar
T1 iso, T2 iso, FLAIR hyperintense, basis for identification
Desmoplastic Infantile Ganglioma
Variant of ganglioglioma occuring infirst 2 years
Cysts are the rule with
Peripheral rim or nodular enhancement.
May have calcified rim
Looks like huge GBM in an infant, but has good prognosis WHO grade 1
T2 hypointense rim due to desmoplasia
Desembryonic neuroepithelial tumor DNET
WHO grade 1
Prepherally, cortex and subcortical WM almost always involved.
Neuroepithelial in origin
Looks like gangliglioma
Present second or therd decade with chronic seizures (again think to the location)
Very bright T2
Septations in triangular pattern
Enhancing (about 1/3)
Usually no edema
Very slow grower.
50% association with cortical dysplasia of some type.
Recurrence is rare
Most frequent priomary solitary intraaxial mass in adult
Circumscribed (WHO I)
pilocytic giant cell
Diffuse (WHO II) least likely to enhance. Most
common in brainstem
gemistocytic exclusively in cerebral hemis.
(80% convert to GBM)
Anaplastic (WHO III)
GBM (WHO IV)
4th and 5th decades
evolve from lower grades
Ill defined borders
prolific vasogenic edema
Likely to enhance.
If there is necrosis, bump to GBM status.
Often predated by diffuse astrocytoma. Mean transformation to GBM is 2 years.
Majority in the ledrly are actually primary, not evolved from lower grades.
Death in few months WHO IV
Evolved GBMs less agressive, younger population
Most common of the astrocytomas.
Characterized by necrosis in the tumor.
High choline levels on MRS, the higher, the worse.
Syndromes associated with brain tumorw
Basal cell nevus syndrome
Astrocytomas>PNET>Chroid plexus tumor
Temproal lobe neoplasms
Astrocytoma, low grade 0-30
Desmoplatic infantile gangliglioma 0-1
GBM variant, about 2%, very nasty
Prefers supratentorial space.
Can be well defined, superficial and well enhancing
May be metachronous or contiguous spread
Associated with NF1
Corpus Callosum masses
Acute shear injury
Subependymal giant cell astrocytoma
Another glioma variant
Classically associated with tuberous sclerosis.
Age range 2-20
near foramina of monro
Enhance (tubers do not)
Projects into the ventricle
A lot of subependymal things enhance that do not on CT, so CT may be better to look for this lesion.
WHO grade 1
WHO grade II
Frequent calcification, cystic
Location: favors lateral or 3rd ventricle
Edema is rare
Peak in third decade.
WHO grade II
Looks very simila to central neurocytoma, but peak is 5th and 6th dacades. M>F
Has calcification, soft tissue and cystic component
Variable appearance depending of cellular composition ratio
Hypo T1, Hyper T2/FLAIR
Hypo or isodense, again depending of cellular composition
Wrose than regular oligodendroglioma
Peak mean is 49
Has everything, hemorrhage, necrosis, calcification, cystic, avid enhancing
At least two lobes are diffusely infiltrated with tumor.
Lack of mass effect or distortion.
Peak age 40-50
WHO Grade III
Bilateral in half of cases (half, get it?)
Subtle. Maybe loss of G/W junction little mass effect
Better, but still subtle.
Diffuse subtle T2 hyperintensity
Minimal enhancing if at all
May degenerate to GBM with rapid growth
48% at 1 year, 27% at 2 years
Anterior third ventricle
WHO grade II
Slow growing, solid, well circumscribed, enhancing
Iso on T1 and T2
May have central necrosis
Age range over 30
Mass effect may cause hydrocephalus
Age: young edults
Well circumscribed, peripheraly enhancing, centrally necrosing. Usually large at diagnosis.
Complete resection curative
Most commonly the diffuse hystiocytic type non-Hodgkins
Often associated with immunodeficiency of some type
Many appearances, mass, coating, malignant effusion
Can spread across corpus callosum
Usually abuts ependymal surface (toxo does not)
Can coat ventricles
Thalium avid (good way to differentiate from Toxo, which is
Hyperdense with dense enhancement is classic, HOWEVER
in immunocompromised patient, can also be hypodense
Variable multiple lesions. Look for correct distribution
Heterogeneous on T2
Marked homogeneous enhancement
Bright on DWI due to high cellularity
Intravascular CNS lymphoma
Focal parenchymal enhancement and/or dural enhancement
Meningial types are most common (Meningo, fibro, etc.)
From there invade the brain.
Of primary parenchimal types, Gliosarcoma is most common
Acts like GBM and arcoma rolled into one.
Favor temporal lobe with invasion of dural surfaces.
Most common pineal tumor of germ cell origin
Age: Adolescents and young adults, rarely over 30
Symptoms: Most commonly Perinaud's syndrome
Precocious puberty if active
Engulfed pineal gland (Ca++ inside pineal inside tumor)
Iso T1, Slightly hypo T2
Responds well to radiotherapy.
CSF seeding is common
Can have cystic component (esp if in unusual location, in which case not as radiosensitive)
Looks about the same as elsewhere.
Second most common germ tumor in pineal region, and also like suprasellar cystern
Distinctly commonly hemorrhagic
Uniquely + hCG and placental lactogen.
High rate of subarachnoid seeding
Peak in 1st decade
WHO grade IV
Highly cellular (round cells)
MRI: Intermediate on T2
Classic: Exploded pineal calcification
Slower than blastoma
WHO grade II
Peak 2nd decade (but mean is 30)
Higher rate of calcification and cyst formation.
Similar signal characteristics to blastoma (hyperdense, intermediate T2)
Highly variable contents
Can calcify and Can have mass effect.
Key is to follow-up and make surer there is no growth over time
Can present with symptoms of hydrocephalus, Perinaud or lid retraction (compression of CNs), seizures
Acute hemorrhage = pineal apoplexy
Location: Anterior third ventricle near foramina.
Positional headaches or hydrocephalus
Age range 30s to 40s
CT: Usually highly proteinacious, therefore hyperdense
MRI: Usually T1 hyper (again protein), T2 variable
Faint rim enhancement possible
Watch or if symptomatic, resect
Location: Mostly in ventricles, centered on choroid
Also sp canal, parenchymal, extraasxial
Mostly follows CSF characteristics on CT and MRI, but may be T1 bright due to debris or high protein
Rare in CNS
Location in CNS
Intradural, extraaxial in cervicothoracic region
Do not enhance
Mass of neural tissue in abnormal location (hamartoma type thing). Have vascular and fibrous tissue.
Can be in auditory canal and mascarade as schwannoma
Residual tumor vs scar
Enh within 1-2 days Yes No
End within 3-4 days Yes Yes
Size with time Increase Decreases
Enh type Nodular, Solid Linear, outside bed
Mass effect/edema Increases Decreases
Dural enhancement at least 1 year, sometimes many years
Granulation tissue enhancement lasts months. Suspect recurrence if still nehancing after 1 year.
Scan within 48 hours for baseline. Suspect residual neoplasm if there is enhancement
CNS post radiation changes
Early usually reversible. Late usually not reversible
Early = within weeks
Early delayed = within months
Late delayed = months to years
Early ED LD
Enh No rare common
Long term none none vasculitis
Ca No No Yes, peds
Necro Leuko No No Rare, chemo
Reversible Yes Yes No
Telangiectasia No No Yes
Hemorrhage No No Often
Can cause mineralizing microangiopathy, especially if coupled with methotrexate-high density calcification in basal ganglionic region.
Residual/recurrent tumor vs rads necrosis
Timing immediate to mths Mths to yrs
Mass effect/edema Yes Yes
Enh Yes Yes (swiss chs)
PET Positive Negative
Thal SPECT Positive Negative
MRS hyper choine hypo choline
Perfusion MR hyper rCBV decr. rCBV
NASCET definiton of stenosis
% stenosis = 100 (distal nl lumen-resid lumen)/distal
ECST def of stenosis
%stenosis = 100 (estimated true lume-resid lumen)/estimate
Significant extracranial ICA on angio
70% stenosis or more
Less than 2mm residual lumen
Reflux from ECA to ICA
Delay of ocular choroidal blush (>5.6 s in >30 year olds)
Filling from contralateral ICA or vertebral arteries.
Stroke on CT
Hypodensity, lacunar or in vascular territory develops hours after stroke and continues developing to about day 2 or 3
Swelling: peaks at about 5 days, gone by about 2-4 weeks. Persistence over 6 weeks implies underlying lesion.
Enhancement possible, usually from about 24 hours and resolves in several weeks.
Fogging: Hyperemia and cellularity (neutrophyls, phagocytes) after reprefusion leads to increased density of infarct lasting from about second to third weeks after the infarct (50%)
Laminar necrosis may result in serpiginous calcification months to years after.
Region slowly becomes hypodense, well circumscribed.
DWI can detect ischemia within about 30 minutes of event and lasts to about 10-14 days
CNS lesions with restricted diffusion
Cortical spreading depression
Lymphma, Epidermoid, PNET
Metabolic disease (Canavan's)
Cerebral blood flow
Normal is 45-110 ml/min/100g of tissue
20-40 is oligemia- underperfused but enough for survival
<20 action potentials cease
About 10 or less, death occurs.
rCBF = rCBV/rMTT
Infectious CNS vasculitis
Involves CNS about 45%, late in disease
Nonspecific hyper T2 white matter lesions
SAH or intraparenchymal hemorrhage
! Aneurysms are unusual in the CNS
CNS giant cell arteritis
Most common neuro presentation is sudden vision loss due to occlusion of ophthalmic artery or headache
Intracranial involvement is rare.
CNS Wegener granulomatosis
High intensity T2 abnormalities in about 28%
Leptomeningeal involvement with enhancement, usually already after history of systemic disease.
Similar to PAN on angio.
Perivascular inflammation, endothelial cell proliferation. Not really true vasculitis.
Stroke from valvular involvement and tendency to thrombosis due to antiphospholipids
Irregular white matter hyperT2 lesions
Stroke, due to aniphospholipds causing thrombosis.
Possibly small vessel vasculitis
Mechanism possibly spasm or thrombosis.
Bleeds from hypertension
Intracranial arteritis (Heubner arteritis)
Focal defitis and encephalopathy
Usually 6-8 years after onset of disease
Usually in children
Dilated calcified vessels. No strokes.
aka Susac's syndrome
Microangiopathy in arterioles of the brain, retina and cochlea.
Results in acute and subacute multifocal encephalopathy, visual loss, hearing loss.
Fluctuating monophasic course lasting months to years.
Look for retinal or cochlear arterial occlusions.
Hyper T2 irregular lesions. Unlike MS, these are usually in basal ganglia and thalamus.
Leptomeningeal hyperintensity on FLAIR
Preference of brainstem and diencephalon.
Narrowin, occlusion, aneurysms, venous predominance.
Cortical involvement is rare (distinction from other vasculitides)
Involves cervicocephalic arteries in about 30%
ICA is most often affected, close to bifurcation.
ECA and vertebrals also fair game
Associated with headaches, TIA, Stroke, dissection SAH (though unclear if this is due to the actual lesions)
Dilated portions of vessel are Greater than the normal lumen!
Slow occlusion and high grade stenoses of distal ICA and first order branches resulting in extensive networks of fine collateral that look like a "puff of smoke" on angio.
Collaterals are mostly from meningeal vessels, basal ganglia perforators or anastomoses from ECA (transdural)
In peds, progressive course with cerebral ischemia, TIA, stroke
In adults, SAH and parenchimal hemorrhage predominates.
On MRI, low flow in distal ICA, and flow voids in basal ganglia representing dilated collaterals.
Can have cerebrovascular occulive disease 5-17%
Children more than adults and only the worst hematologic disease.
Direct occlusion of arterioles is NOT the problem
Instead there is stasis in vasas-vasorum, resulting initimal and medial hyperplasia narrowing and eventual occlusion of LARGE vessels.
Anterior and middle most often involved, posterior circ spared.
Parenchymal infarcts can be seen
Malignant lymphoma restricted to intracranial vessels.
Recurrent strokes, TIA, encephalopathy, seizures.
Multiple hyper T2 lesions.
Occlusions of medium vessels on angio
radiation can cause endothelial degeneration, intimal fibrosis, fibroblastic proliferation of media.
Strokes can result months to years after injury.
Characteristic abnormal T1 and hyper T2 in the globus pallidus bilaterally.
Hypodensity on CT
Encephalopathy can happen rarely about 3 weeks after injury and can involve globus pallidus, U fibers, internal/external capsule with high T2 signal and thalamus, putamen with low T2 signal (this is due to iron deposition).
Restricted diffusion evident in injured white matter
Elevated lactate and reduced NAA on MRS indicate irreversible injury.
Stages pf hemorrhage
Time T1 T2 stuff
Hyperacute <6 Hr Dark Bright oxy Hb
Acute 8-72 hr Iso to low Low deoxy Hb
Early subacute 3-7 days High Low Intra MetHb
Late subacute >1 week Bright Bright Extra Met Hb
Chronic >months Dark Dark Hemosid
Primary intraparenchymal hemorrhage causes
Aneurysm: Mycotic or congenital
Hemorrhagic infarct: Arterial or venous
Drugs: Cocaine, Amphetamine, L-asparaginase
Any hematologic bleeding disorder
Any acquired coagulopathy
Causes of subarachnoid hemorrhage
Same lesion as everywhere else, justin calvarium.
Sessile: expands through diploe of skull. More common.
Can occur anywhere in the skull, but prefers frontal and parietal.
15% are multiple.
Well defined lytic lesion with a radial pattern of trabeculation.
Involves outer table and spares the inner.
Avid homogeneous enhancement
Variable uptake on bone scan can be slightly low or high.
Disorders assoviated with aneurysm
Too many to write them all
All the intracranial vasculitides.
Familial idiopathic nonarteriosclerotic cerebral calcification syndrome
Hereditayr hemorrhagic telangiectasia.
Aneurysm sourse by bleed location
Interhemispheric fissure and lateral vent-ACOM
4th ventricle- PICA
Most common cause of SAH is aneurysm rupture
Blood is hyperdense initially, but sensitivity drops rapidly with age on CT (80% within 3 days, 70% in 5 days, 50% after a week, 30% after 2 weeks)
On MRI acute SAH is very difficult. CSF has high oxygen pressure, so most of the Hb is in the oxy form (iso on both T1 and T2) and stays that way for a long time.
Tap will get you a bloody or xanthochromic CSF.
MRA for aneurysm can be done i f
Worst headahce, but low suspicion of aneurysm
Family history of aneurysm (PKD in family etc.)
Follow-up of unruptured aneurysm
Need to know diagnosis but can't treat
Angio is contraindicated.
As much as 4% rehemorrhage in 24 hours, 1-2%/day in first 2 weeks
Vasospasm risk increased days 3-15, major cause of poor outcome
Non-aneurysmal perimesencephalic SAH
Sudden onset of headache and SAH in the perimesencephalic region without evidence of aneurysm.\
No extension of blood any further.
Blood resolves on f/u in 1 week
Mass of telangiectatic vessels in the brain
Variable size, average 3 cm.
Between the vessels is NORMAL tissue
enhancing nodule in Pons
Cerebral lesions can occur in association to Osler Weber Rendu (aka hereditary hemorrhagic telangiectasia)
Appears as a high density lesion on CT
Can calcify and enhance
Are congenital vascular hamartomas
There is no interposed normal brain tissue.
May be surrounded by gliosis.
Predilection for cerebral hemispheres and brain stem.
Shows blood products of various ages.
! Complete rim of hemosiderin
No feeding arteries.
Can have an early vein or blush
May present with
These are mass effect-like findings
Network of dilated medullary veins converging in radial fashion to a large draining vein.
Can drain deep or superficially.
No feeding arteries.
Classic angio is an ealy draining vein and blush or persistence of abberant veins.
Propensity for paraventricular area.
Most are asymptomatic and do not bleed.
Is an actual drainage for normal brain. Venous infarction can follow if this runoff is closed off.
Has one or more enlarged feeding arteries and enalrged early draining veins.
Slowly enlarge by recruitment and become symptomatic usually in 20s or 30s.
Hemorrhage rate ~4% per year.
The older you are, the less likely to hemorrhage
Symptoms by mass effect, pulsation, steal from normal brain.
Prone to aneurysm formation.
Syndromes associated with vascular CNS malformations
Venous hypertensive encephalopathy
Elevated venous pressure and decreased perfusion secondary to dural malformation leads to dementia-like symptoms.
Important because potentially reversible by treating the malformation.
Results from rotational acceleration. Axons stretch and can fully tear.
Severe DAI = immediate coma or impairment.
Areas which are more prone
Body and splenium of corpus callosum
MR is best for detection
May be DWI positive
Superior cerebellar peduncle
Overall inferomedial forces push brain down.
Temporal lobe compresses CN 3 - ipsi blown pupil
Compression of posterior cerebellar and anterior choroidal arteries can cause local infarcts.
Contralateral cerebral peduncle compression - ipsilateral motor weakness = Kernohan-Woltman notch phenomenon.
Overall force is from one side to the other.
Cingulate gyrus shift beneath the falx.
COmpression of anterior cerebral artery can result causing focal infarcts.
Absence of spontaneous respiration
No brain stem reflexes
Negative Technetium-HMPAO scan
Transtentorial foramen magnum herniation
Absence of intracranial flow voids
Poor G/W junction
No intracranial enhancement
But nl intravascular enhancement with
prominent nasal and scalp (hot nose sign)
Look for many lesions of different ages (by blood age)
Can have any type of blees, DAI, cervical hematoma.
Seizure, ecchymoses, vitreous or retinal hemorrhage etc.
Global ischemia leading to
Poor G/W junction
Generalized cortical low density,
Basal ganglia high or low.
Cerebellum is nl, because more resistant
Fracture of lateral wall of orbit
Fracture of inferior orbital rim and floor.
Fracture of zygomatic arch.
Also lateral wall of maxillary sinus.
Usual route is from mastoids or paranasal sinuses into the epidural space.
Syphilis is just about the only primary cause.
Epidural low density mass
T1 hypo or iso
Can cross midline
Confined by sutures
Same as an abscess, but in the subdural space.
Much more common than epidural.
More common supratentorially.
Possible hyperintensity of underlying brain.
Restrict diffusion. (hygromas do not)
Paranasal sinusitis (older children, aduls)
Purulent bacterial meningitis (infants)
Osteomyelitis of calvarium
Otitis media, mastoiditis
Tratment is drain with wide craniotomy
Most often by direct extension. Hematogenous spread is less common
Imaging is usually normal, especially if already treated.
Distended subarachnoid space.
FLAIR hyper of subarachnoid fluid.
Acute general cerebral swelling.
Enhancing leptomeninges (not prognostic, and more common with bacterial)
Present with headache, stiff neck (most common)
Carcinomatous vs bacterial meningitis
Bacterial tends to be leptomeningeal - follows contour of brain (pia, arachnoid)
Carcinomatous tends to be pachymeningeal - follows contour of calvarium (dura)
Idiopathic hypertrophic cranial
Inflammatory disease (sarcoid)
Mets, including skull
Idiopathic hypertrophic cranial pachymeningitis
Rare. Inflammatory infiltrate in dura.
Presents with severe headache, cranial nerve palsies, ataxia
Peak in 6th decade.
Chronic course, some improvement with steroids.
Vision loss if optic nerve sheath involved.
Dural thickening like pseudotumor
T2 hypo, without involving brain.
Related to pseudotumor, Toloso-hunt, other fibrotic diseases.
Most common cause is hematogenous seeding.
Frontal and parietal MCA distribution.
Predominantly preadolescents and middle age.
Single, multiple, unilocular, multilocular, you name it we have it
Procession: Early cerebritis 1-3 days, late cerebritis 4-9 days, early capsule 10-13 days, late capsule over 14 days.
Capsule is thicker on the gray matter side owing to better blood supply and therefore better immune response.
Capsule is collagenous and maybe contains free radicals and therefore dark on MRI.
Internal contents are T1 hypo, T2 hyper. Low density on CT.
May restrict centrally in necrotic region.
Most evoke considerable surrounding edema (if not, suspect something else)
Hemorrhage is rare.
Spectrum of meningitis or postoperative.
Can present with enlarge ventricles, enhacing endymal rim. Possible choroid enhancement.
Periventricular calcification can occur after the fact.
Pitfall-ependymal enhancement also occurs in HIV rlated lymphoma or malignancies spreadin subependymally.
Hemorrhagic seeding due to high vascularity.
Nocardia and Cryptococcus have special propensity.
Rare since there is a BBB there. Most often not seen alone, but in conjunction with other infection; encephalitis, meningitis.
Asymmetry of choroid
CNS septic embolus
Often associated with infective endocarditis, also IVDA
Most often Strep pneumo is the organism, but just about anything can do it.
Protracted course with mass effect, enhancement over 6 weeks.
CNS herpes simplex
Most common cause of fatal endemic encephalitis
Survivors can have severe memory loss, personality changes.
Type 2 responsible for neonatal infections (direct transfer during birth and also part of TORCH with all the problems thereof)
Features of neonatal herpes
Hyperdensity of gray matter
Intracranial calcifications 17-21 days after infection
Low density, high intensity parenchymal abnormalities-gyriform enhancement
Type 1 responsible for child and adult infections.
1-3 cases per million
Rapid progression to Stupor and coma
Seizures, viral prodrome, fever also common
Asymmtric involvement of anterior temporal lobes, insula, orbitofrontal region, cingulate gyrus. Basal ganglia are very rare and late finding.
1/3 primary 2/3 reactivation
HIgh intensity T2/FLAIR in first 5 days, DWI variable
Very subtle to about 5 days, then has hypodense lesions
Gyriform enhancement, later turning in hyperdense regions.
CNS Herpes zoster
Like immunosuppresed (Particularly with lymphoma) or elderly population.
Casued by reactivation.
Can have involvement of ophthalmic nerve, can even infarct.
High T2/FLAIR and low density on CT
Gyriform enhancement in segmental distribution.
Vasculitis with mutiple segmental constricitons.
Shigles associated with ipsilateral posterior column atrophy.
Agressive early treatment with acyclovir.
Can also cause meningitis, ventriculitis.
Bilateral symmetric high T2/FLAIR regions without enhancement.
Headache, N/V, fever, nuchal rigidity, cerebellar ataxia, parkinsonism 1-3 weeks after chickenpox.
ADEM is major differential.
Subacute sclerosisng panencephalitis
A secondary demyelinating disease of viral etiology.
Affects young children 3-9, m>f
Slow viral infection post measles, particularly if before 18 months.
Intellectual deterioration, ataxia, chorea, dystonic rigidity, SZ,
myoclonus, vision deterioration including cortical blindness
Unresponsiveness, autonomic dysfunction
Marked elevation of gamma globulin on CSF labs, measles antibodies.
Hyper T2/FLAIR lesions
Basal ganglia particularly putamen
Enhancing with mass effect early in course
Disease is Infectious mono. Can also have Guillan-Barre, mutiple CN palsies.
Predictable T2/FLAIR hyperintense lesions
Can have enhancement of U fibers (worse symtpoms)
Brain stem tumor
Eastern equine encephalitis
Short prodrome then
AMS, SZ, focal deficits.
Periventricular and cortical are less common
None are specific
Throughout asia, mosquito borne virus
Rapid progression to coma after predictable fever, headache, ams. Can have extrapyramidal signs.
Bilateral T2/FLAIR in thalami and putamina.
Thalamic lesions prone to hemorrhage
Usually does not enhance.
HIV is neurotropic
40% pts have some neurologic symptoms and 75% on autopsy.
Very nonspecific appearance.
White matter lesions, diffuse encephalitis and the like.
Cerebral infarctions in about 30% on autopsy (only about half that with symtpoms), most often in basal ganglia.
AIDS dementia complex
Involved WM and deep gray
Diffuse pallor of centrum semiovale, atrophic changes.
High T2/FLAIR in WM, basal ganglia, caudate nuclei without enhancement
No real corelation to state of immunosuppression.
Important to differentiate from Lymphoma. Delaying tratment for either is bad. Mistaken toxo treatment believed to decrease efficacy of radiation on lymphoma.
High density mass on non-contrast CT, or ventricle encasement, iso on T2, thallium takeup better for lymphoma.
T2 hyper, hemorrhage, ring lesion better for Toxo
Most common cause of fetal and neonatal viral infection.
Before 18 weeks gestation causes agyria
Propensity for ependymal and subependymal regions
Classic-bilateral periventricular calcifications (as compared to neonatal toxo which has calcifications all over including curvilinear basal ganglia calcifications)
Usually involves brain by hematogenous seeding, but 19% have no evidence extrameningeal disease at time of diagnosis.
Can lead to intracranial tuberculoma
Likes brain stem, possibly most common lesion worldwide
Variable on MRI
May adhere to dura gicing false appearance of meningioma
Exudative meningitis most often involves basal cysterns.
Involvement of perforating vessels may cause basal ganglia infarcts (vertical rising up from basal cystern along perforator territory)
Also CN palsies
Agressive treatment with ABx and follow-up imaging to gauge response.
Uniform dense enhancement of basal cysterns
But usually negative for organisms
Gm + rod
Causes meningitis, meningoencephalitis. Abscess is rare.
No specific appearance, but likes brainstem (rhombencephalitis)
Likes impared cellular immunity, diabetics, alcoholics, post-transplant.
Nonspecific T2/FLAIR lesions small to large, possibly nehancing.
Can involve parenchyam, meninges, CNs, pons, thalamus, basal ganglia (really anything)
BUT most often, the scan is normal!!!
Yeast with thick capsule (india ink test)
Causes meningitis, meningoencephalitis, granuloma formation.
Usual vector is hematogenous spread from occult pulmonary nodule.
3rd behind HIV and Toxo for CNS infection in AIDS
Suspect with dilated Virchow-Robin spaces in young pt.
Multiple miliary enhancing parenchymal leptomeningeal nodules including choroid plexus, trigone, spinal cord and nerve roots.
Same process as widened VR spaces can dilate basal cysterns, hydrocephalus by mass effect.
Endemic to southwest U.S., north Mexico
If intracranial at all
Thick basilar meningitis
Meningeal and parenchymal granulomas
Can cause ependymitis.
Dilated V-R spaces like crypto
Focal infarctions due to vasculitis.
Hyper PDW/FLAIR in cysterns
Most vulnerable are
diabetics with ketoacidosis
debilitated with burns
People on iron chelator deferoxamine also apparently vulnerable
Fungus rapidly destroys mucosa leaving black eschar
bloody nasal discharge
dark swolen turbinates
cranial nerve palsy
progresses rapidly to stroke, encephalitis, death
rim of soft tissue thickenss along walls of sinuses
obliterated nasopharyngeal fat planes
Low T1 and T2 in sinuses.
can see bony destruction.
! major tendency to proliferate along vascular structures, producing arteritis, aneurysm, pseudoaneurysm, abscess.
After extension to orbit, can extend to brain
In that case makes low density abnormalities in anterior cranial fossa with mass effect, possibly enhancing
Can cause large vessel cerebral infarction
Aerobic fungus resembling aactinomyces, but without the sulfur granules.
Infects severely immunocompromised, especially due to steroid therapy.
Can be complication of many diseases
CNS seeding usually by hematogenous spread from pulmonary nidus.
Usual manifestation is abscess (enhancing capsule with septations.
Meningitis is rare.
Identification is critical, since nocardia is treatable with sulfonamides
May or may not have complete enhancing capsule (distinction from nocardia)
Infects the immunocompromised.
CNS spread by innoculation or hematogenous seeding from pulmonary nidus, extension from sinuses.
Agressive in the CNS producing meningitis, meningoencephalitis, hemorrhagic infarction.
If less agressive, can make abscess or isolated granulomas.
T2/FLAIR even T1 hyper lesions.
In sinuses can be hypointense due to manganese accumulation (susceptibility)
Subtle areas of low density with minimal mass effect out of proportion to afressive clinical features.
Most common cuase of autopsy proven non-AIDS cerebral mycosis
Likes neutropenics on steroids.
Gets to CNS by hematogenous spread
Causes vascular inflammation, thrombosis, infarction, microabscesses. Possibly noncaseating granulomas.
Hydrocephalus by obstruction
various enhancing nodules
calcified granulomas (and raw ones too)
Septisemia may result in endophthalmitis
Protozoan parasite found everywhere.
Acute toxo in immunosuppressed is usually reactivation, not new infection
Can manifest as vascular thrombosis with infarction or localized abscess.
In acute toxo, calcification is not common (for congenital, very common)
multiple T2/FLAIR hyper lesions with vasogenic edema and ring or nodular enhancement on T1.
CT areas of low density iwth little or no enhancement, gyriform enhancement, or isodense enhancing nodules.
Promt response to antibiltics can be diagnostic vs lymphoma
Human beings are the only definitive hosts.
Larval form does well in the CNS.
Ingested from insufficiently cooked pork, fecal-mouth transfer.
Most common manifestation is seizure.
Cyst and scolex develop after several weeks after infection.
Symptom onset average is 4.8 yrs (1-30)
Can be found in
parenchyma (cortical and deep gray matter)
subarachnoid space (suprasellar, cerebellopontine angle cystern)
ventricles (4th most common)
spine is rare ( only 3%) can cause spinal cord compression
calcification in parenchyma, classic off center
spherical 1-2mm diameter scolex surrounded bu 7-12 mm fully calcified sphere., which only occers in dead larvae
Cyst is clear (follows CSF signal)
Minimal edema (barely any T2/FLAIR)
Acute encephalitis is more common in children
and lasts 2-6 months, can be fatal,
Ring enhancing lesions
CT better than MR (hypointense T2 nodule)
The evolution can take average 5 years (2-10)
Symptoms are site dependent
Ventricular can result in hydrocephalus or granular ependymitis.
Rare, only a bout 2% if cases.
Involves CNS by oclusion of small vessels causing cortical infarction.
Involves brain 2-27% of cases.
Fluke penetrates perivascular soft tissue in foramina of the skull to gain access, through meninges, directly into brain.
exudative aseptic inflammation
infarction on one side of brain
granulomatous lesion around the worm
Multiple conglomerated, interconnected granullomas around a focus, which the calcify in chronic stage giving "soap bubble calcifications"
Migrating adult tapeworm.
In CNS causes
Chronic granulomatous lesions with cebral atrophy, organising edema, gliosis.
Multiple punctate calcifications (in smooth muscle of dead worm)
Variously shaped enhancing lesions or granulomatous lesions ( I gather can outline the worm, though it is not always actually in there)
Associated with ipsilateral ventricular atrophy
After surgical removal, granulomas can regress
Raised intracranial pressure
Embryo matures into large cyst, commonly large and unilocular, but can have daughter cysts.
Cerebral involvement in 2-5%
Most common location is paritetal lobe
Severe chmical encephalitis results from cyst rupture
Systemic granulomatous disease peaking in 3rd and 4th decades.
CNS involved in about 5% cases symptomatically, but 16% on autopsy
More common consists of
chronic basilar leptominingitis
possibly uni- or bilateral CN palsy (VII)
endocrine electrolyte disturbance
communicating hydrocephalus is common
Granulomatous process spread from leptomeninges up V-R spaces thrombosing blood vessels
CNS has elevated lymphocytes and protein, low glucose.
parenchyal sarcoid nodules
associated with extensive arachnoiditis and
microscopic granulomas throughout
obstructive hydrocephalus if in periaqueductal
Nodules act like intracranial mass
High intenstiy WM
T2/FLAIR hyper parenchyma and G/W junction
Diffuse gyriform enhancement
nodules may calcify
can cavitate, but not as frequently as TB
meningioma (especially if extaaxial)
25% have aphthalmic manifestations
Anterior uveitis (most common)
lacrimal gland involvement
optic nerve/sheath involvement
Dramatic response to steroid
Necrotising granulomas in multiple organ systems.
Meningeal thickening and enhancement
Brain or spinal cord
Nonspecific w/m T2.FLAIR lesions
Produces a vasculitis resulting in peripheral neuropathy.
Can involve pituitary and stalk
Multisystem immune vasculitis
CNS involved in 5-10%
Brain stem syndrome or
Meningoencephalitic syndrome or
Body symptoms and neuro symptoms don't have to correlate in time, sometimes years apart
multiple high intesity lesions
CLASSIC most common - mesodiencephalic junction lesion with edema extending along tracts in brain stem and diencephalon.
optic nerve (rare)
majority under 50
Venous thrombosis common
Other vasculitides (primary arteritis)
Inflammatory diseases (sarcoid)
Granulomatous disorder due to delayed immunity to bacterial agent.
CNS involved in 20%
Can be agressive leading to coma and death
No specific CT or MR
an have T1 hypo, T2 hyper and enhancing nodules.
Classic: man 40-50 with myoclonus, aphthalmoplegia, progressive dementia, statorrhea, malabsorption, arthritis!! high suspicion of Whipple
Autoimmune Demyelinating polyneuropathyProgressive motor weakness and hyporeflexia/areflexia
Can also involve VII th nerve.
Increased CSF protein without pleucytosis. Delayed nerve conduction on EMG
Variant of Guillain-Barre with acute onset of external ophthalmoplegia, cerebellar ataxia and areflexia
Contrast enhancement in abduscens and oculomotor nerves as well as spinal nerve roots
peak 6-8 years
Focal motor seizures followed by
progressive loss of ipsilateral motor fuction
neuronal loss without inflammation late in disease
May be some sort of delayed autoimmune reaction to viral pathogen
Treatment is hemispherectomy
therefore important to note involvement of basal ganglia as removal makes worse morbidity.
large regions of diminished cerebral perfusion
Crossed cerebellar diaschisis (deminished perfusion in contralateral to the affected area)
Decreased NAA, elevated Cho, Glutamate (nonspecific of course)
Acute necrotising encephalopathy of childhood
Age 5 mths to 11 years (asia)
After infectious encephalitis episode
Elevated liver enzymes, lactate dehydrogenase, ammonia
Elevated CSF pressure
Elevated CSF protein, myelin basic protein
multifocal symmetrical lesions with thalami affected in all cases, internal capsules in most.
Survivors have motor and cognitive sequelae
cystic white matter changes
Differential is very long
Acute encephalopathy with hemorrhagic shock
Acute poisoning with hydrogen sulfide
Glutaric aciduria I
Inflammatory viral dise
Symmetrical thalamic degeneration with calcifications of infancy
Viral or postinfectious encephalitis
Primary demyelinating disease
Secondary demyelinating disease
Subacute sclerosing panencephalitis
Central pontine meylinolysis
Disseminated necrotising leukoencephalopathy
Benign paramesencephalic SAH
•Is a diagnosis of exclusion
•Classic distribution of blood is in the subarachnoid spaces around the midbrain, prepontine and interpeduncular
•After the diagnosis is established (2 normal angios), no further intervention or imaging is necessary
Heterogeneous group of diseases characterized by enzyme defects that result in abnormal myelin production and turnover
Mostly nonspecific imaging and clinical presentation
General imaging for leukodystrophy
Abnormal T2/FLAIR WM signal, usually symmetric
Periventricular, deep or subcortical WM
Key imaging features
Symmetric bilateral posterior involvement
Splenium, peritrigonal, corticospinal tracts, fornix, commissural fibers, visual/auditory pathways
Usually spares subcortical U-fibers
Abnormal contrast enhancement along the margins of WM involvement
Classically peritrigonal demyelination
Presence of contrast enhancement correlated to disease progression
MR spectroscopy data correlates well with clinical severity of disease
Typically, increased lipids with lactate peak/doublet, Increased myoinositol, and increased choline peaks. Indicative of cell membrane breakdown (lipids)/lactate production, gliosis (mI), and cell proliferation (Cho)
Clinical: May present with skin bronzing, behavioral problems, hearing problems
X-linked adrenoleukodystrophy: severe progressive form affecting pre-teen males
Progresses to spastic quadriparesis, blindness, deafness, vegetative state
Without BMT, death may result in 2-5 years
Early bone marrow transplant may stabilize white matter loss, rare reversal of WM injury
Specific subtype of wedge fracture where the posterior bone is driven into the sinal canal
Results from severe axial loading.
Often associated with
Vertical fractures of laminae and spinous process
Widening of interpeduncular distance.
Most often occurs at thoracolumbar junction, with 50% at L1
UNSTABLE! since at least 2 columns are involved.
Look for widening of interpeduncular distance and non-visualized posterior cortex line on plain radiographs.
Most commonly present with headache and fever. May present with seizures, altered mental status, and focal neurologic deficits.
Stages of abscess evolution include
early capsule, and
Key point: Contrast enhanced imaging demonstrates a well-defined, thin walled, enhancing rim.
Usually thicker on gray matter side.
Early cerebritis: Mild patchy enhancement.
Late cerebritis: Irregular rim-enhancement.
Early capsule: Low density center thin, enhancing rim.
Late capsule: Shrinking cavity and thickening capsule.
Early cerebritis: Ill-defined hypo/iso T1 and hyper T2 signal.
Late cerebritis: Hypo T1 center, iso/hyper T1 rim, hyper T2 center, hypo T2 rim, and surrounding hyper T2 edema.
Early capsule: Hyper T1 center, hyper T1 rim, hypo T2 rim.
Late capsule: Cavity shrinks, capsule thickens, and edema lessens.
Lactate and amino acids peaks.
Treatment is via surgical drainage and/or excision. For abscesses <2.5 cm, treatment with antibiotics only may be effective. Steroids can be used for edema.
After acute ischemic infarction, the obstructing t hrombus or embolus is slowly lysed, eventyally leading to reperfusion. If the BBB is already broken down in the ischemic area, hemorrhage occurs. This usually happens 6-12 hrs after the infarct (almost always by 48 hrs).
Late conversion: The mechanism is similar, but reperfusion is established from collateral, which takes about a week to develop.
On autopsy, about 40% of infarcts are actually hemorrhagic to some degree (maybe patechial)
Cerebral amyloid angiopathy
NOT amyloid in tissue.
The amyloid is deposited in the media and adventitia of small and mediam vessels in superficial cerebral cortex and leptomeninges, sparing basal ganglia and other deep nuclei.
Increases with age, but not corelated with HTN.
Result is loss of elasticity of the vessels, microaneurysms and fibrinoid degeneration. The wakened vessels can rupture.
Hemorrhage usually lobar, frontoparietal.
Can present as subdural or subarachnoid.
Propensity for multifocal and recurrent hemorrhages.
Multiple cavernous malformations
Previous traumatic injury
Late post radiation nectrolsis
again, NOT associated with systemic amyloidosis
Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarction and Leukoencephalopathy
Inheriter arterial disorder.
Presents with recurrent TIAs and CVAs starting around 40 or 50, usually resulting in stroke and death within 20 years.
Deteriorate with subcortical dementia, incontinence, pseudobulbar palsy
On MRI, hyperintensity in WM of external capsules symmetrically. Cortex and cerebellum are spared.
Hemosiderin deposition in large portions of leptomeninges, subpial tissue, spinal cord and cranial nerves due to repeated bleeding.
Pyramidal tract signs,
CN II, V, VII and VII usually involved, VIII is worst (hence the hearing loss).
Is best, rim of susceptibility over everything.
Hemorrahgic shock and encephalopathy syndrome
Hypoxic/anoxic damage resulting from infectious or toxin-mediated mechanism.
Hyperpyrexia a reported factor.
2-33 months general age range.
Clinical criteria: Shock, coma seizures, diarrhea, DIC, anemia low platelets, elevated LFT, renal dysfunction, acidosis all with neagtive blood/CSF cultures.
CT: diffuse low density regions, basal ganglia, cortical subcortical. Intraparenchymal hemorrhage.
MR: hemorrhagic products, cortical lesions.
Autoimmune demyelinating diseases
and their manifestations:optic neuritis, transverse myelitis, acute hemorrhagic leukoencephalitis
Viral demyelinating diseases
Subacute sclerosing panencephalitis
Vascular demyelinating diseases
Subcortical infarction and leukoencephalopathy
Metabolic demyelinating diseases
Combined systems diseases B12 deficiency
Toxic demyelinating disease
Disseminated nectrotizing leukoencephalopathy
Most common demyelinating disease
Peak age range 30 years
Symptoms: Cranial nerve palsy, optic neuritis, vague sensory complaints progressing to paresis, paraplegia of limbs, myelopathy.
Symptoms are separated in space (neural location) and time.
CSF shows IgG bands (70%
MRI must have 3/4
1 enhancing or 9 T2 bright lesions.
One or more infratentorial
One or more juxtacortical
Three or more periventricular
Dissemination in time
Enhancing lesion seen at least 3 months after clinical attack
If no enhancing lesion, after additional 3 months there is an enhancing lesion or new T2 bright
Most common course is relapsing remitting (85%)
Also: secondary progressive (relapsing progressive), Primary progressive (seems to have fewer imaging lesions despite progressive course). Malignant type is rapid progressive.
MR T1 black holes (old) and T2 bright lesions (new), predilection for periventricular pericolossal regions, visual pathways, subcortical, cerebellar peduncles, posterior fossa. High intensity lesions at Colossal-septal interface is highly specific for MS vs vascular demyelination.
Lesion may have mass effect (tumefactive MS), in which case associated with seizures. These have leading enhancing edge (incomplete ring). Veins go THROUGH these, as opposed neoplastic lesions which displace veins.
Enhancement window is about 2-8 weeks (though can be up to 6 months and may precede the clinical lesion (which makes sense).
Magnetisation transfer is a new technique that can bring out more lesions.
Differential: Lyme, Vasculitides (primary angiitis, PAN, Behcet's, Syphilis, Wegener's, Sjogren, SLE), Hypertensive ischemic lesions, Virchow robin spaces, Migraine, Trauma, UBO's
Spinal cord MS
Spinal cord alone up to 24%, but brain and cord involvement is more common.
Predilection for cervical cord (60%)
Most are multifocal (56%)
Lesions do not involve the entire cord, are peripheral, 90% span less than 2 vertebral bodies.
Can cause cord swelling, but rare (up to 14%)
No correlation between cord lesion load and the EDSS
MS associated syndromes
all these seem to MS variations, not clearly proven to be separate entities.
Enlarged spinal cord differential
Transverse myelitis from MS or ADEM
Tumor, either primary or mets
Infection: toxo, hiv, herpes zoster
Diffuse leptomeningeal coating: Sarcoid, Lymphoma, other tumors
Osteitis Fibrosa Cystica
A condition of advanced bone demineralization with formation of brown tumors due to hyperparathyroidism.
Classically associated with primary. However now most common in patients with secondary hyperparathyroidism due to renal disease.
Diffuse demineralization of the bone occurs. In more severe cases advanced brown tumors may form, and can be multifocal.
Imaging: diffuse demineralization with many cystic appearing lesions throughout. Brown tumors can be seen, possibly compressing neural structures.
People less than 40 may have high signal abnormalities on imaging. Predominantly Centrum pellucidum
Acute disseminated encephalomyelitis
A secondary demyelinating disease of autoimmune etiology.
Usually a history of recent viral illness, vaccination, URI, exanthematous disease
Frequently associated with measles, varicella, mumps or rubella, also Epstein Barr, CMV, M Pneumoniae etc.
Suspected mechanisms is cell mediated immunity to myelin basic protein
Symptoms similar so a singe episode of MS
Lesions may be multile and large, high on T2 and may enhance in nodular or ring pattern
! no new lesions should appear on MR 6 months after onset, but incomplete resolution of lesions is allowed. Gray matter lesions can occur.
ADEM can enlarge spinal cord or brain stem, but usually seen in cerebrum
Clinical syndrome: Transverse myelitis, cranial nerve palsy, acute cerebellar ataxia, optic neuritis.
Rare fulminant variant = Hurst's disease
Progressive multifocal leukoencephalopathy
A secondary demyelinating disease of viral etiology
Caused by JC virus, which infects oligodendrocytes, but pathologic only in the immunocompromised.
Can occur anywhere in the brain.
My be solitary or multifocal
MR: Focal region of low T1 with high T2, most often nonenhancing.
Histologically, multifocal demyelinating plaques involving subcortical U fibers and sparing the ribbon and deep gray matter.
Usually fatal, death approximately 6 moth to 1 year after symptom onset.
Top differential: Post-Infectious progressive encephalitides, other progressive encephalopathies
Secondary demyelinating disease of viral etiology.
Remember, HIV is actually neurotropic.
Diffuse white matter changes with volume loss in a young person.
Conditions associated with PML
Immunosuppressive therapy for other
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy
A secondary demyelinating disease of vascular etiology.
Caused by mutation of Noch 3 gene, chromosome 19
Mean onset in 30s. Mean age of death is 59
Characterized by recurrent TIAs, strokes, dementia, depression, pseudobulbar palsy, hemi- or quadriplegia.
Affects frontal lobes, temporal lobes, insula.
MR: High T2 in white matter, particularly periventricular and deep, basal ganglia, and brain stem. Possibly sub-insular subcortical lacunar lesions representing distended vascular spaces at G/W junction. Low T1 lesions also distribution of deep perforators. Frequency of MR lesions increases with age dramatically.
!Typically involves the U fibers and anterior inferior temporal lobes, inferior frontal lobes.
Cutting edge: Increased diffusivity and loss of diffusion anisotropy can be correlated with clinical impairment. Possibly due to neuronal loss and demyelination.
Post anoxic encephalopathy
A secondary demyelinating entity
Occurs after anoxic episode severe enough to cause coma.
Pt recovers in 24-48 hours then precipitously declines within 2 week period, progressing to coma and death.
Most likely allergic demyelination caused by exposure to myelin antigen during the hypoxia.
MR: high T2 throughout white matter particularly corpus callosum, subcortical U fibers, internal/external capsules. Low T2 in thalamus and putamen sometimes. Also restricted diffusion similar to CO2
Reversible posterior leukoencephalopathy syndrome. A secondary demyelinating entity.
Usually severe hypertension due to many different etiologies can result in high intensity signal in cortex and subcortical white matter in occipital and parietal region.
Usually reversible. Can extend into nearby regions like temporal and frontal lobes, pons, cerebellum
May or may not enhance.
Variety of symptoms including headache, seizure, cortical blindness, confusion, drowsiness, other visual disturbances.
May need diffusion images to differentiate from ischemic infarction.
Bilateral basal ganglia lesions
Enlarged Perivascular Spaces
Lacunar Infarction: Atherosclerotic, Other Vasculopathy; Vasculitis
Manganese Toxicity: Liver Disease; Hyperalimentation, Hypoxic-Ischemic Encephalopathy
Neoplasm: CNS Lymphoma; Astrocytoma
Neurofibromatosis Type 1
Toxin Exposure/Drug Abuse
Central pontine myelinolysis
Secondary demyelinating entity
Happens with rapid correction of hyponatremia, usually iatrogenic, and usually in alcoholics, the debilitated or malnourished. Also associated with renal failure, liver disease, diabetes, disequilibrium syndrome, inappropriate antidiuetic hormone secretion.
In peds, has been associated with orthotopic liver transplant, AML, Hodgkin's, Wilson, craniopharyngioma.
Patient deteriorates subacutely after the correction progressing to coma, quadriparesis, pseudobulbar palsy, extrapyramidal symptoms.
May involve extrapontine structures actually, including thalamus, putamen, caudate, all capsules, claustrum, amygdala, cerebellum
Often can seen normal intensity descending corticospinal tracts outlined by the white matter hyperintensity.
No mass effect or enhancement.
Causes optic nerve palsy, necrosis of putamen and subcortical white matter.
Caudate and hypothalamus can be involved.
Also can produce hemorrhage.
Affects thalamus and pons
Few case reports on imaging: symmetric hyperintensity within the basal ganglia, thalami, and brain stem, possibly restricted diffusion within the white matter tracts of the corona radiata.
Atrophy of cerebrum, corpus callosum, cerebellar vermis.
High t2 in white matter, poor G/W differentiation, low signal in basal ganglia and thalamus.
Can produce low or high intensity on T1, high T2 in globus pallidus. Also effects hippocampus.
Organic mercury toxicity.
aka Minamata disease
Affects calcarine area, cerebellum, postcentral gyri.
Characteristic presentation: contracted visual fields, ataxia, sensory disturbance.
Disseminated necrotising leukoencephalopathy
Secondary demyelinating entity.
Can occur after radiation to brain with methotrexate in children, chemo in adults, bone and soft tissue sarcoma, small-cell lung CA.
Progressive neurologic disorder characterized by decreasing mental status, seizures, progressing to coma and death
CT: Marked low density white matter
Path: axonal swelling, multifocal demyelination, coagulation necrosis, gliosis
Predilection for periventricular white matter and centrum semiovale, sparing U fibers.
MR: diffuse high T2 throughout white matter, possibly enhancing.
Intrathecal chemo CNS changes
Often injury is noted when chemo is combined with radiation.
Sometimes when chemo is intrathecal, there can be focal necrosis with high T2, low density on CT and enhancement adjacent to the catheter.
A dysmyelinating disease (most common)
Autosomal recessive. Due to deficiency of aryl sulfatase A, which hydrolyzes sulfatides to cerebrosides.
Myelin is no degraded or reused. There is resulting accumulation of ceramide sulfatide in macrophages and Schwann cells. Sulfatide (lipid) granules found in neurons. There is diffuse myelin loss in central and peripheral nerves.
Symmetric demyelination wit sparing of U fibers.
Several pediatric varieties separated by age of onset.
Adult form has multifocal lesions in white matter with propensity for frontal lobes and atrophy with ventricular dilatation.
MR: Symmetric high T2 in white matter and cerebellum. Rarely enhances.
A dysmyelinating disease
X-linked or autosomal recessive variants
Consists of cerebral degeneration and adrenal cortical insufficiency.
Cause by acyl-CoA synthetase preventing breakdown of very long-chain fatty acids with accumulation in white matter, adrenal cortex, plasma and RBCs
Clinical: Impaired hearing and vision, abnormal skin pigmentation, hypotonia, difficulty swallowing, behavioral, seizures.
Can progress form anterior to posterior or reverse. The advancing edge represents zone of dysmyelination with enhancement. Nonenhancing regions are gliotic.
Imaging: Enhancement of major white matter tracts including corticospinal, spinothalamic, visual, auditory, dentatorubral. Also calcifications in trigone or around frontal hons, mass effect in advancing edge, isolated frontal horn involvement.
MR: relative sparing of U fibers. Entire length of spinal tracts can be involved.
Vanishing white matter disease
Seen in children and teenagers.
Clinical: Prominent ataxia, spasticity, optic atrophy, relatively preserved mental capabilities.
Chronic progressive course with decline associated with episodes of minor infections and head trauma.
Cortex is relatively normal.
White matter is largely destroyed with exception of some sparing of U fibers.
Cystic degeneration from frontal to occipital lobes with temporal lobe least involved. In noncystic regions, there is diffuse, severe myelin loss.
MR: Regions of white matter with signal similar to CSF on pulse sequences. Brain is swollen with cystic degeneration around the periventricular region. Cerebellar atrophy, p
corpus callosum hypoplasia, retardation, adducted thumbs, spastic paraparesis and hydrocephalus secondary to aqueductal disorder (part of Bickers-Adams I guess?)
Normal pressure hydrocephalus
Triad of wacky wobbly and wet.
Confirmatory tests: CSF withdrawal trial, Indium labeled cysternography with ventricular reflux and no flow over convexities after 24-48 hours, Marked aqueductal flow void, trial of ventricular shunting.
Most accurate predictors of positive response to shunting: absence of central atrophy or ischemia, gait apraxia as the dominant clinical symptom, upward bowing of corpus callosum, prominent CSF flow void, a known history of intracranial infection or bleeding.
Only about 50% will improve with shunting.
aka benign enlargement of of the subarachnoid spaces in infants.
Possibly due to immaturity of arachnoid villi, unable to keep up with CSF production.
Typically presents at less than 2 yrs old with rapidly enlarging head circumference.
Neurologically the child is normal.
Associated with prematurity, history of intraventricular hemorrhage, some genetic syndromes.
CT/MR: Dilatation of the CSF spaces over frontal lobes along interhemispheric fissure, but relatively normal sized ventricles.
Usually resolves buy age 3-4, head circumference returns to normal (rather the chart catches up)
Differential: Chronic subdural hygroma atrophy due to previous injury.
Typical pt is child with shunt presenting with nausea, vomiting and fever.
30% failure in 1st year, 50% in 6 years.
Shunt infection is about 10% in first year.
Imaging: Compare ventricular size with prior, stress the temporal horn and third ventricle, these dilate first. Contrast normally clears from shunt tube in 3-10 mins in kids, 10-15 in adults. Evaluate from reflux of contrast into ventricle (should not happen). Look for spillage if contrast into peritoneum. This should be the norm.
Mechanisms: Obstruction of cath tip, valve malfunction, tubing is kinked, obstruction of peritoneal end, disconnection
Slit ventricle syndrome
After a while, especially if there are problems, shunted brain can lose compliance and ventricles remain tiny even if the pressure is high.
Also can be due to overdrainage. Calvarium thickens in this case
Idiopathic benign intracranial hyperplasia.
May be due to decreased absorption of CSF at arachnoid villi or increased water content of brain, increased resistance to drainage due to venous obstruction.
Typical patient is an obese (95%), black (62%), young to middle age female.
Clinically: Frequent headaches particularly on waking up, cranial nerve palsies, papilledema or visual field deficits.
Associations with pregnancy, endocrine abnormalities, medications, intracranial venoocclusive disease.
Exclude dural venous malformation or venous thromboses as cause, these can have high morbidity if missed.
LP demonstrates extreme elevations of CSF pressure .
Imaging: Ventricles either normal or slightly small. Cerebral subarachnoid space is slightly large. Most MR studies are normal, although there can be subtle increased white matter T2. Venous sinuses and veins may be small and may enlarge after LP. Optic nerve sheath complex is enlarged. There is reverse cupping of optic nerve corresponding to degree of vision loss.
Treatment is repeat LP. Spontaneous remission is frequent. Shunting may be necessary. Diuretics and carbonic anhydrase inhibitors can help
Semantic variant: 40% Temporal lobe atrophy and parahippocampal regions. Hemispheric asymmetry, left more often than right. SHort term memory usually intact. Long term memory and semantic functions worst hit.
Frontal variant: 40% Anterior temporal and frontal atrophy. Hemispheric asymmetry.
Progressive nonfluent aphasia variant: Perisylvian and insular atrophy, esp. superior temporal gyrus. Progression over years to mutism.
Progressive supranuclear palsy
Parkinson's like features plus severe supranuclear ophthalmoplegia (impaired downward gaze), gait disorder, dysarthria, postural instability and pseufobulbar palsy few years after inital onset.
Patients present with hyperextension of the neck, contracted facial muscles resulting in "surprised look".
Imaging: Dilation of 3rd ventricle, atrophy of midbrain, possible decreased substantia nigra, collicular atrophy, high T2 periaqeductal gray, increased putaminal iron
Cortical-basal ganglionic degeneration
Postural instability, dystonia, akinesis, apraxia, myoclonus, bradykinesia, limb rigidity. Neuronal loss in SN, frontoparietal cortex and striatum.
Imaging: Asymmetric thinning of pre- and postcentral gyri, central sulcus dilation, atrophy of paracentral structures, superior parietal lobule, knife blade atrophy, particularly superior parietal lobule and superior frontal gyrus.
Central sulcus asymmetry is characteristic.
Temporal and occipital lobes less involved.
Possible subcortical gliosis with corresponding T2 signal.
Rare autosomal recessive disorder affecting bile acid synthesis. Deficiency causes elevated cholestanol levels, tendinous xanthomas, early cataracts, diarrhea, osteoporosis, polyneuropathy, spasticity.
Occurs in childhood.
Deep gray matter (globus pallidus), supratentorial white matter (corticospinal tracts esp in cerebral peduncles) may demonstrate focal T2 high signal. May be dentate nuclei microcalcifications visible on CT. Possible enlargement of V-R spaces.
In spine selectively affects posterior and lateral columns.
Cerebellar involvement may extend throughout white matter from the dentate nucleus.
Prototype pt-Young, with cataracts plus symmetric deep gray matter lesions and posterior column lesions.
Area of focal encephalomalacia that communicates with the ventricular system, causing appearance of focal dilated ventricle.
CSF pulsations may cause remodeling of bone.
Possible synechiae within the ventricle, causing ball-valve phenomenon and progressive enlargement of ventricle with skull expansion.
As opposed to schizencephaly, there is no gray matter lining.
Pathologic basal ganglia calcifications
Hypoxic-Ischemic Injury, NOS
Congenital Infections (HIV, CMV)
Endocrinologic Disorders (Hyperparathyroidism, Hypoparathyroidism, Pseudohypoparathyroidism, Pseudopseudohypoparathyroidism, Hypothyroidism)
Radiation and Chemotherapy
Common with various things
May have reversible nystagmus, ataxia, peripheral neuropathies, slurred speech.
Occurs in young adults
Associated with cerebellar and brain stem atrophy
Pons, inferior olives, cerebellar peduncles are strikingly small.
Marked cerebellar atrophy, particularly vermis.
Clinical: truncal and limb ataxia, problems with speech, mild mental impairment.
Sporadic and autosomal dominant forms exist.
Cerebellar olivary degeneration
Cortical and cerebellar degeneration with selective atrophy of the lateral cerebellum (fish mouth deformity), superior vermis (esp. declive, folium and tuber).
Fourth ventricle and primary semilunar fissure are markedly enlarged. Olives are secondarily reduced in size.
Primary defect is in the cerebellar cortex.
Hereditary cerebellar atrophy
Distinct from Friedrich ataxia. Produces dramaic cerebellar atrophy.
Seen in middle ages patients with severe vermian atrophy and lesser involvement o the remaining cerebellum.
Clinical: Lower extremity gait ataxia, optic atrophym aphthaolmoparesis in later life.
Slow but relentless progression.
Another hereditory cerebellar atrophy syndrome.
aka Louis-Bar syndrome
Autosomal recessive disorder characterized by cerebellar vermian and hemispheric atrophy and telangiectatic lesions of the face, mucosa and conjunctiva.
Has associated abnormality of immune system causing recurrent sinus and lung infections.
Associated with leukemia and Non-Hodgkin lymphoma.
Death usually in childhood.
If surviving to adulthood-high risk of multiple organ cancers.
Imaging: Vermian/holocerebellar atrophy and white matter high signal. Possible occult intracranial cardiovascular malformations-dark dots on gradient echo sequences due to hemosiderin
Hypertrophic olivary degeneration
Many causes-ischemic, traumatic, neoplastic or vascular insult-to the components of the "triangle of Guillain and Mollaret (dentate nucleus, red nucleus and inferior olivary nucleus), which are connected by the superior cerebellar peduncle, central tegmental tract and inferior cerebellar peduncle. Lesions in the tracts lead to deafferentation of inferior olivary nucleus leading to atrophy after first 2 months, followed by hypertrophy between 6 months out to 3-4 years.
Clinical: Palatal tremor aka palatal myoclonus.
Nitochondrial Encephalomyopathy, Lactic Acidosis, Strokelike episodes
Is a rare nitochondrial disorder.
Imaging: Multiple areas of cortical high signal on T2, offen crosses traditional cerebral artery distribution. May be bright on DWI, but ADC is not low-therefore not infarcts
Can cause cortical blindness and lesions resolve in time with minimal residual sulcal dilataion. Lesions can also occur in putamen, caudates, thalami and may or may nor enhance.
Eventually posterior cerebral atrophy develops.
MRS: elevated levels of lactic acid.
Another mitochondrial disorder
Myoclonus, Epilepsy, Ragged Red muscle Fibers
A lot like MELAS, but myoclonus is distinguishing feature as opposed to strokelike episodes in MELAS
other enzyme syndromes
All presents with some type of seizure, vomiting, delayed brain maturation and myelination syndrome. First swelling, then atrophy with abnormal meylin.
Tay-Sach's GM2 disease
Low dnsity in parietooccipital white matter, atrophy, thick skull, lenticular opacitis, brachycephaly, craniostenosis
3-hydroxy-3-methylglutaryl-coenzyme A lyase deficiency
What no name?
Problem with leucine metabolism
Mental status changes
Leukodystrophy with preferential involvement of deeper arcuate fibers on MR.
Macrocephaly with open opercula and abnormally high signal in B-G esp G-P.
May present with encephalitis.
Subarachnoid space dilatation andterior to temporal lobes
B-G volume loss.
Mehylenetetrahdrogolate reductase deficiency
A type of hyperhomocystinemia
MR: severe atrophy and hpomyelination
MRS: reduced NAA
Btaine treatment may reverse these findings.
Cystathionine beta synthase deficiency. Chromosome 21
Multiple thrombotic events, arterial and venous, including strokes
Lens subluxations (up and in)
May also hve osteporosis, cataracts, scoliosis, biconcave vertebral bodies.
Maple syrup urine disease
Branched chain amino acid disorder
US: symmetric echogenicity of periventricular white matter, B-G mainly paladi, and thalami
CT and MR: diffuse edema in similar locations and cerebellum, capsules.
MRS: 0.9 ppm peak representing branched chain aminos
Also delayed myelination
Propionic ecidemia, Mehtylmalonic ecidemia
Both affect tricarboxylic cycle
Both lead to metabolic acidosis.
Detected within 1st month
High frequency in Saudi Arabia-autosomal recessive
Abnormal white matter signal
B- lesions (G-P in MMA and Putamina in PPA)
MRS; Lactate peak
White matter demyelination posteriorly, often optic radiations
nuonal migrational abnormalities
cerebellar and brain stem high signal foci
Glutaric acidemia type II
Acyl CoA dehydrogenase
G-P and white matter T2 hyperintensities
Bt-wing dilatation of sylvian fissures
Temporal arachnoid cysts.
Trends of myelination
Posterior to anterior
Central to peripheral
Motor to sensory
Inferior to superior
Disorders of primary neurulation
Predominantly affect the spinal cord and include those due to adhesions between the endoderm and ectoderm-presumed etiology for neurenteric cysts and diastematomyelia.
main anomaly is holoprosencephaly
Since premaxillary facial structures are associated with ventral induction, there are common defects such as cyclopia and probosci
Overproduction of neurons
Associated with achondroplasia, Soto syndrome, Beckwith-Wiedemann
Most common congenital cystic abnormality of the brain.
Consists of CSF collection within layers of arachnoid
Most common locations suprantentorially:
Middle cranial fossa
subarachnois space over convexities
Most common locations infratentorially
Cerebellopotine angle cistern
Quadrigeminal plate citern
Intraventricular rare, but can happen
CT: Fluid density mass effaces sulci and may remodel adjacent bone (but not much) Does not enhance. If intrathecal contrast it used, it will eventually diffuse in.
NR: Follows CSF signal
Differential: Subdural hygroma, dilatation of normal subarachnoid space, epidermoid
Distinguishing feature: Cerebral veins are displaced inward (they are on the inner leaflet of arachnoid) unlike subarachnoid collections.. Scalloping is nots een in hygromas.
Rathke cleft cyst
Embryologic remnant of Rathke;s pouch. Lined with single layer of cuboidal or columnar epithelium.
Arises from sella or suprasellar.
Fairly common-13% on autopsy series.
Can compess normal posterior or anterior pituitary, causing hypopituitarism
MR: Well defined maa with variable T1 and high T2 (depending on protein content)
Differential: Craniopharyngioma, hemorrhage into pituitary.
No calcifiation or enhancement
Meninges protrude through skull or spinal canaland include neural tissue.
Interestingly meningoencephaloceles are mor common than meningoceles.
Associated with Chiari II in occipital region.
Next most common are parietal and frontal (each about 10%)
Association of nasofrontal or sphenoethmoidal location among southeast asian women. These are often clinically occult and may be taken for nasal polyp (and removal attempted).
Anterior meningoencephalocele associations: agenesis of corpus, colobomas, cleft lips
CT: CSF density protrusion through a bony defect in calvarium.
MR: Continuity of meningocele with underlying leptomeninges.
May arise wtihin ependyma of ventricular system (lateral ventricle most common, near glomus)
Imaging: Follow CSF intensity, but may be bright onT1 due to high protein, mucin, cholesterol .
Lining is epithelial.
Differential: epidermoid cysts, cysticercosis, echinococcal cyst
Often diagnosed on obstetric US when no brain is seen.
Elevated alphafetoprotin on labs.
Association with spinal dysraphism
The portions of the brain supplied by anterior and middle circulation is gone, replaced by large CSF collection.
Parts of the brain supplied from posterior are intact-will often see posterior portion of temporal lobes, occipital lobesm thalami, infratentorial structures.
Differential is maximal hydrocephalus where there is a thin mantle of neural tissue plastered up against the skull. This affects the occipital lobes too.
Best seen on MR, to look for the thin tissue of hydrocephalus.
Constellation of congenital abnormalities where separation of right and left cerebral hemispheres is incomplete. Ranges from septo-optic dysplasia, where only a bit of septum pellucidum is absent, to alobar holoprosencephaly (horseshoe shaped single ventricle with no separation of lobes at all).
Hypothalamus is at least partially fused even in mildest forms, also cingulum and caudate nuclei.
In alobar, even basal ganglia and thalami are fused and corpus is gone.
CT: Absent or only partially formed falx, interhemispheric fissure, lateral ventricles. Corpus typically gone, 3rd ventricle abnormal. Olfactory bulms may also be absent.
Maximal hydrocephalus is a main differential. Look for a well formed falx, cortical mantle plastered againt the skull and separated ventricles.
This is the one lesion where posterior portions of corpus callosum may be formed, but anterior portions are absent. (except the rostrm, which forms after the splenium)
Associations: Caudal agenesis
Fetal alcohol syndrome
Trisomy 13. 15. 18
Mildest of the holoprosencephaly spectrum
Septum is at least partially absent, in which case usually the anterior portion is what's left.Small hypoplastic optic nerves. Small optic chiasm
60% have abnormal hypothalamic pituitary axis resulting in low hormonal state (usually growh hormone)
Associated with seizures.
50% associated with neuronal migration disorders
Congenital optic nerve hypoplasia
This is a syndrome of small hypoplastic optic nerves associated with low hormonal state due to abnormal hypoplastic pituitary axis and absent posterior bright spot. Sounds familiar? Seems an awful lot like septo-optic dysplasia, except the pellucidum is intact.
Abnormality of neuronal migraion thought to occur in 5th to 7th week of gestation (possibly watershed infarct) resulting in gray-matter lined celft from ventricle to pial surface of the brain.
Usually the cleft is polymicrogyric.
Closed lip or open lipped variants.
Associated with focal cortical dysplasia (ppolymicrogyria), gray matter heterotopias, agenesis of septum pellucidum (80-90%), pachygyria.
Locations by descending order: Frontal, frontoparietal, occipital.
Clinical: Seizures, developmental delay, developmental sydphasia
Agenesis of Corpus Callusom
Fairly common (about 0.7% of live births)
Presents with refractile seizures and mental retardation.
Development proceeds from genu posteriorly to splenium and then rostrum. Therefore if splenium is gone, so is the rostrum despite being on oppsite sides.
Complete agenesis is most common followed by loss of splenium.
When spleniumm is gone, there is physical appearance of copocephaly.
In complete agenesis, there is high riding posteriorly oriented third ventricle with parallele and widely spaced lateral ventricles. There are Probst bundles.
Associated with other midline abnormalities: interhemispheric arachnoid cyst, pericallosal lipoma, incomplete formation of hippocamapal region, no cingulate sulcus.
Associated congenital abnormalities: Agyria, pachygyria, heterotopias, dandy-walker, holoprosencephaly, cephaloceles, chiari I and II, trisomy 13,15,18, fetal alcohol syndrome, Meckel syndrome, Aicardi sydrome
Abnormal proliferation of normal tissue in abnormal location.
In CNS affinity for the hypothalamic region followed by cerebral cortex-subcortical region, even periventricular.
Clinical: present with precocious puberty, occasionally visual disturbances. Boys > girls. Seizures common or gelastic seizures.
Imaging: Isodense and isointense to normal brain. Identified by distortion of local architecture. Bulbous protrusion of the hypothalamic region in the midline
Disorganized brain tissue, usually gray matter, located in the wrong place due to abnormal migration in 7th to 16th weeks.
Clinical: Usually pt has seizures, weakness, spasticity, hyperreflexia, developmental delay.
Nodular types: Subependymal and subcortical variants. Possibly x linked. If subcortical, may have abnormal sulcation. Affected hemisphere may be atrophic
Band types: Associated with severe developmental delay and earlier onset of seizures. Also seems to be x-linked-the gene predisposes men to lissencephaly, and women to band heterotopia.Appears as smooth, well defined band of gray matter in the wrong place. Thin band of white matter separates from normal gray matter resulting in "double cortex" sign.
Incomplete lissencephaly. Characterized by short broad fat gyri caused by abnormal sulcation and gyration of the cortex.
Congenital and the insult is likely a 12-24 weeks. Neuroblastic migration does not process all the way to superficial layers.
Bright T2 rim may be seen around the cortex due to laminar necrosis in the cell-sparse layer of the cortex.
Most severe form of pachygyria with no sulcation at all, just a smooth surface. Seems to be X linked
Possibly due to ischemic laminal necrosis of the 5th cortical layer after 20th week. By this time neurons have reached the cortex.
CMV infection is implicated but not proven. Otherinfections also being investigated.
Associated with chiari malformations and schizencephaly.
Clinical: Developmental delay, spasticity, seizures.
Imaging: White mtter thickeness is normal (as opposed to hemimegalencephaly-increased or pachygyria-decreased).
Can not distinguish pachygyria from polymicrogria on MR-all the microgyru run together.
Congenital bilateral perisylvian syndrome
Polymicrogyria involving opercular cortex associated with abnormal sylvian fissure sulcation.
Presents with seizures, pseudobulbar paresis, devopmental delay.
Abnormal sylvian fissue may have cortical thickening on both sides. Also associated with schizencephaly
Focal cortical dysplasia WITHOUT balloon cells
Source of seizures. Any imaging characteristics are very soft.
Balloon cell focal cortical dysplasia (of Taylor)
Imaging: Cortical thickening, hyperintense subcortical white matter on T2, radial bands from the ventricle to cortex, which may be white or gray matter intensity. G-W junction is blurred. In fact appearance is similar to a tuber.
Clinically presents with seizures and sensory motor deficits.
Enlargment of all or part of the cerebral hemisphere.
Associated with polymicrogyria or agyria on the affected side.
MR: Distorted thickened cortex with ipsilateral ventricular dilatation (unique feature). Heterotopias are characteristic. Delayed myelination. Overall white matter volume is increased. High intensity rim of laminar necrosis may be seen if there is lissencephaly.
Clinical: Seizures, hemiplegia, develomental delay, abnormal skull. The enlarged side may have been small in infancy.
Associated syndromes: Neurofibromatosis, Soto syndrome, tuberous sclerosis, klippel-trenaunay-weber syndrome, proteus syndrome
Similar manifestations to neurofibromatosis and encephalocraniocuaneous lipomatosis.
Can present with hemimegalecephaly, subependymal calcified nodules, periventricular cysts, irregularly shaped vertebrae. Also macrocephaly, macrodacryly, hemihypertrophy, cutaneous nevi, soft tissue tumors, lipomatosis.
Thought to be congenital abnormality rather than neoplastic due to persistence of meninx primitiva (neural crest portion that forms the neural tube).
Most common site: interhemispheric fissure, followed by quadrigeminal plate cistern, pineal region, hypothalamic region, cerebllopontine angle cistern.
They do not grow. Symptomatic only secondary to other associated defects. 50% associated with agenesis of corpus.
rare entity consisting of loss of cerebellar hemispheric separation with fusion of the hemisphere through the midline. There is no anterior vermis. Dentate nuceli and middle cerebellar peduncles are fused. Deficiency of posterior vermis. My also have agenesis of septum pellucidum.
Males > females
Asymmetric skull due to partial premature closure is plagiocephaly.
Lambdoid suture closure leads to Turricephaly (high riding vertex)
Metopic suture-trigonocephaly with a ridge runnign down forehead
Coronoal - brachycephaly (short fat head)
Autosomal dominant or recessive (recessive is worse as usual)
Calvarial involvement frequent in both
Clinical: usually due to skull base foraminal stenosis-cranial nerve palsies, optic atrophy, stenosis of jugular and carotid foramina.
May cause framatic herniation of tonsils due to lack of space inside.
Most common dwarfism.
Small foramen magnum, large head.
Short clivus, platybasia, J shaped sella.
Spinal senosis ue to short pedicles.
Flattening of the skull. Present when the basal angle formed by intersecting lines from the nasion to tberculum sellae, and from tubreculum aloing clivus to anterior aspect of foramen magnum is greater than 143 degrees.
Associated wtih Klippel-Feil, cleidocranial dysplasia and achondroplasia.
Clinical: hearing loss, mental retardation, autism, speech defects
Ocular: Cataracts, galucoma, pigmentary retinopathy
Migration anomalies rare
Parenchyma: necrotic foci, delayed myelination
Basal ganglia and cortex calcifications
OTher: Patent ductus, pulmonic stenosis, rash, hepatosplenomegaly
Congenital Herpes simplex
Clinical: skin lesions
Ocular: chrioretinitis, microphthalmos
Head size normal
Parenchyma: Hydanencepahly possible
Pathcy areas of lw density in cortex and WM, vast encephalomalacia, cotical laminar nectrosis. NO PREDILECTION TO TEMPORAL LOBE unlike the acute encephalitis.
Clinical: Usually fetal death, but if survives, developmental delay, seizures.
Head: microcephaly, unless there is hydrocephalus to push things apart
Parenchyma: Hydrocephalys from aqueductal stenosis. Intracrainal calcifications
alcifications: mostly periventricular, also BG and some in parenchyma.
Other: hepatosplenomegaly. rash.
Most common of the congenital infections
Clinical: Hearing loss, Psychomotor retardation, visual defects, seizures, optic atrophy
Frequent neuronal migration abnormality
Associated with microcephaly.
Parenchyma: Hemorrhage, esp at germinal matrix. Loss of WM, delayed myelination, sybependymal cysts around occipital horns, cerebellar hypolpasia, atrophy.
Calcifications: Frequent, periventircular, but can have cortical too.
Asymptomatic at birth, eventually developmental delay, late spastic paraparesis, ataxia
associated with microcephaly
Parenchyma: glial microglial nodules in basal ganglia, brainstem, WM. Demyelination, atrophy, corticospinal tract degeneration.
Vasculitis with calcifications.
Calcifications: perivascular in basal ganglia, cerebellum
Other: neck adenopathy, oral candidiasis.
Absent nasal septum
Granulomatous: Sarcoid or Wegener's
Tumor: Lymphoma - NKT lymphoma or B cell
In the setting of fetal distress leading to or from: Placental abruption, meconium aspiration, prolapsed umbilical cord, uterine rupture, severe placenta previa.
Apgar scores diminished at birth with acidosis, hypotonia, lethargy, seizures.
4 main patterns : deep gray matter, watershed cortex, periventricular white matter, mixed. All are usually bilateral and symmetrical.
Basal ganglia injury becomes symptomatic earlier because of high metabolic rate
Asphyxia before 32 weeks gestation age
Dramatic often bilateral injury to thalami, subcortical white matter, basal ganglia, posterior brain stem. The posterior structure affected more.
Deep gray structures become hypodense on CT, hyperechoic, bright on T1. Contrast enhancement is a bad sign
Partial asphyxia in premies
Classical pattern of periventricular lekomalacia: White mater isult due to watershed ischemia in perforating arteries. Cystic cavitation and necrotic areas in periventricular location, often dramatic. Posterior predominance with most severe changes around the trigone.
On US, hyperechogenicity of periventricular WM in the first 2 days (isoechoic to choroid). After a few weeks, these areas are replaced by cystic cavitated areas on the echogenic background. Later lateral ventricles expand with cerebral volume loss.
Grading: 1) evanescent pericentricular echogenicity lasting less than 7 days.
2)prolonged periventricular echogenicities lasting greater than 7 days.
3) Periventricular lesions evolving into small cysts.
4) Periventricualr lesions evolving into extensive cysts.
Periventricular lesions involving the subcortical white matter and creating extensive periventricular and subcortical cysts.
Partial asphyxia in term infant
Cortical watershed distribution lesions between cerebral arteries. Long term consequences include ulegyria (mushroom shape brain due to atrophy of the watershed regions).
Cortex in the deep region of the sulci suffers more than the superficial cortex.
Profound asphyxia in term infant
Greater involvement of lateral thalami, corpus striatum, hippocampus and dentate nuclei. Cortex is spared except around the central sulcus region.
Imaging: low density deep gray structures on CT, high signal on T1 within 2-3 days post-partum
Associated with subependymal hemorrhage on early MRI with parenchymal destruction, periventricular signal alteration and widespread cerebtal infarction, usually in MCA distribution.
Parenchyal periventricular encephaloclastic cysts are a bad prognostic sign.
Focal hemispheric parenchymal lesion alone are not predictive of cerebral palsy
Germinal matric hemorrhage
Occurs in premature infants in the immature germinal matric.
90% occure within the first week.
Though to be venous in origin.
Imaging: Hydrocephalus secondary to clot, plugging up aqueduct of arachnoid villi occurs in 70%.
1) Limited to germinal matrix
2) Germinal matric and intraventricular
3) Germinal matric and intraventricular with hydrocephalus.
4) Germinal matrix, intraventricular and intraparenchymal
Congenital vascular malformation in brain
The only one that presents in infancy is vein of galen aneurysm. Tremendous shunting cuases high output CHF. Congenital cardiac anomalies may coexist. Can be seen on prenatal US of the head.
High bilirubin results in globus pallidus high signal. Abnormality resolves with normalization of bilirubin
Mesial temporal sclerosis
Common source of seizures in adolesv=cents and young adults.
Need thin slices in perpendicular plane to temporal axis.
Causes not well understood, possibly something to do with febrile seizures of childhood. Clinically presents in or after adolescence.
Atrophy can extend to the amygdala (12%), Hippocampal head (51%), body (89%), tial (61%). These areas may have high T2 signal
20% of cases are bilateral.
Loss of normal cortical interdigitations of the hippocampal head
Ipsilateral fornix and mamillary body may be atrophic due to decreased input.
When there are symptoms, the seizing side may have meningeal enhancement.
Autosomal dominant in 50%, the rest sporadic
10-38% of pts with optic gliomas have NF1
15-40% OF nf1 patients have optic gliomas
Astrocytomas seen in cerebellum, brain stem, cerebrum. Also increased incidence in Sp Cord.
Imaging: high signal intensity foci in peduncles, deep gray of cerebellum, brain stem (esp pons), basal ganglia (esp GP), supratentorial white matter. The lesions decrease in size with age, but rarely can enlarge instead, in which case consider an associated neoplasm (astrocytoma).
Look for enlargement of optic nerves or chiasm (low grade pilcytic astrocytoma), which are slow growing and do not reuiqre treatment until symtomatic.
Diagnose clinically: 2 or more of the following 1)6 or more cafe-au-lait spots, 2) or more Lisch nodules, 3) 2 or more neurofibromas or =>1 plexiform neurofibroma 4) acillary/inguinal freckling 5) 1 or more bone dysplasias or psudoarthrosis of a long bone 6) optic nerve glioma 7) diagnosed first degree relative.
Strongly associated with NF1
Sheets of collagen and Schwann cells that spread agressively insinuating around a nerve in circuferential manner.
Tend to involve scalp, neck, mediastinum, retroperitoneum, cranial nerve V and orbit.
The mass is soft and elastic, is the cuase of elephantiasis.Higher rate of malignant transformation than regular, and a lot higher than schwannomas.
Only about 1/10 as common as NF1
Fewer skin lesion than NF1, but tends to be bilateral.
Clinical diagnosis: 1 of the following 1)bilateral vetibular acoustic schwannomas, 2) diagnosed 1st degree relative and a single acoustic schwanoma or 2 of (schwannoma, neurofibroma, meningioma, glioma) elswhere. Can also often see posterior lenticular capsular cataract.
CN V is second most common site of schwannoma in NF2, sendory roots more than motor.
Acoustic schwannoma may be accompanied by arachnoid cyst
Increased incidence of meningiomas, but glial tumors are rare.
Neurofibromas are in fact not a common feature of NF2.
63-90% of patients have spinal involvement
Imaging: enhancing masses in and aroung the cerebellopontine angle or edtending into the internal auditory canal. Generally slightly hyperintense on T2.
Most commonly is a sporadic disease, but can be autosomal dominant (less common)
Characteristic findings: Adenoma sebaceum (up to 90%), menral retardation (50%), Seizure (up to 80%). All three occur in only about 1/3. Also possible are retinal hamartomas (50%), shagreen parches (up to 40%), ungual fibromas (20-30%), rhabdomyomas of heart (25-50%), andiomyolypomas of kidney (up to 90%), cystic skeletal lesions.
Intracranially: periventricular subependymal nodules, cortical and subcortical periheral tubers, white matter hamartomas, subependymal giant cell astrocytomas.
Associated with cortical heterotopias and ventriculomegaly.
most periventricular subependymal nodules are calcified, but only 50% of the parenchymal ones.
Location of cortical tubers highest in frontal lobes followed by parietal, occipital, temporal, cerebellar. The cerebellar ones are associated with older age of onset and more extensive disease with possible cerebellar atrophy.
MR: : curvilinear straight thin bands arising from ventricles (88%), wedge with apex near ventricle (31%), tumefactive foci (14%). Tubers, nodules and white matter lesion may enhance slightly, but the number and size are unrelated to severity of disease.
SGCAs enhance commonly and uniformly, lower rate of calcification than other nodules.
Hamartomatous proliferation of meningeal cells via blood vessels into cerebral cortex. Leptomeninges are thick and infiltrated with fibrous tissue. May be clacified.
Meningovascular fibroplastic proliferation along VR spaces also seen in psammomatous calcification, causing tram tack appearance.
Resembles Sturge-Weber on imaging, but there is no vascular abnormality is present.
Melanoblasts from neural crest cells present in globes, skin, inner-ear, sinonasal cavity, leptomeninges are source.
Characterised by cutaneous nevi, melanotic thickening of meninges.
Imaging: diffuse enhancement of meninges of brain and spine (20%). May lead to hydrocephalus, craial neuropathies and syringohydromyelia.
Malignant degeneration of skin lesions uncommon, but about 50% transfomration of brain lesions. Prenchymal or intramedullary infiltration is hallmark.
Longitudinal split in the spinal cord. Split may involve all layers of meninges resulting intwo dural sacs. Two hemicords in one sac are mor common though.
Usual location is the lower thoraco-lumbar region T8-T12 about 25%, the rest in lumbar.
Associated with bon abnormalities such as spina bifida, wide interpediculate distance, hemivertebrae, scoliosis. Hiry skin patches in 75%.
Also associated with tethered conus, chiari II, myelomeningocele and hydrosytingomyelia.
Imaging is best with MR.
Cord generally unites below the cleft.
Filum terminale abnormalities
Lipomas-are a form of dysraphism. Range from scant fibrolipomas to chunks of fat communicating to subcutaneous region through bony defect.
Thickening and tethering can be without fat at all.
Normal filum is 2 mm or less.
Associated with: kyphoscoliosis, midline bony defects in lumbosacral regionm, fatty infiltration of filum
Caudal regression syndrome
Truncated blunt spinal cord in the lower thoracic level associated with incomplete formation of sacrum and genitourinary tract.
Most commonly in children of diabetic mothers.
Pathognomonic appearance-wedge shaped conus terminating at T12 level.
Most benign form of spinal dysraphism.
Cord and thecal sac are normal.
THere is a tuft of hair with a small subcutaneous cyst at level of coccyx. May be associated with a dermal sinus as a higher level. A sinus may communicate with thecal sac, providing a tract for spread of infection. Therefore must be removed with prejudice.
Cause is failure of cutaneous ectoderm/neuroectoderm separation.
Cavity in the cord that may be due to contral canal dilation or a cavity eccentric to the central canal.
Mostly associated with congenital malfomrations including the Ciari spectrum and myelomeningoceles. May also arise due to trauma, sichemia, adhesions, neoplasms.
Pitfall-dilated central canal in conus medularis (5th ventricle), a normal variant.
Anastamotic pathways between internal and external carotid
All go thorugh aphthalmic artery from internal carotid
On the external carotid side
Superficial temporal: Suprotrochelar artery, supraorbital, internal palpebral
Internal maxillary branches: Anterior deep temporal, Middle meningeal, Infraorbital artery, Sphenopalatine
Facial artery branches: Angular artery, Lateral nasal artery
Marfan - up and out
Homocystinuria - down and in
Also: Ehlers-Danlos, GEMSS syndrome, Weill-Marchesani syndrome
literally "white pupil" because light does not reach retina.
Nonspecific sign of many conditions including
Retinoblastoma (about 50%)
persistent hyperplastic primary vitreous
Toxocara canis infection.
retinopathy of prematurity
chronic retinal detachment from
Most common intraocular tumor of childhood
Usual presentation before 3 (98%) with leukokoria, strabismus, decreased vision, retinal detachment, glaucoma, ocular pain, signs of ocular inflammation.
Most are sporadic, but about 10% familial autosomal dominant (these more commonly bilateral and multifocal). Chromosome 13. This also associated with high incidence of non-ocular tumors: midline primitive neuroectodermal, pineal, asteogenic sarcoma, soft-tissue sarcomas, melanoma, basal cell carcinoma, rhabdomyosarcoma.
Has a rare diffuse infiltrative form, without a mass. This presents at mean age 6, unilateral with retinal detachment, thich irregular nodular leaflets, frequent viterous dissemination. Calcification is rare, confusible with Coat's disease
Mets usually occur wtihin 2 years of treatment.
Often occurs in the pineal (the third eye also thir testicle), in which case associated with bilateral type.
CT: calcifications in the posterior globe with extension into vitreous. Homogenous or irregular. Up to 95 % of pts. Absence inf calcification makes retinoblastoma highly unlikely, esp in the young population.
MR: Moderately elevated T1, low T2.
Persistent hyperplastic primary vitreous
Persistence of portions of the primary vitreous with hyperplasia of associated embryonic connective tissue. May present as leukokoria.
Usually microphthalmic, possibly small flattening of anterior chamber.
Funnel shaped mass of fibrovascular tissue including hyaloid artery persisting in the retrolental space. Runs in S shaped course thorugh Cloquet canal between back of lans and head of optic nerve.
! Does not calcify unlike retinoblastoma!
CT: look for the S shaped canal
MR: variable intensity, again, look for the Cloquet canal
Toxocara canis infection
Child ingests soil contaminated soil. Ova hatch in gut and migrate everywhere. Ocular infection results when the larvae get into the eye and proceed to die. Resulting inflammation causes vitraous opacification and retinal detahcment.
The ocular lesions occur months to years after inital infection. The chronic endophthalmitis causes unilateral leukokoria.
CT: diffuse hyperdenstiy in globe WITHOUT calcification. There may be thick enhancement of the sclera.
MR: High T1 and T2 in globe.
Due to prolonged oxygen therapy in premature infants. Severity is related to birth weight, amount of O2 used, gestational age at birth (younger the worser)
Can present as bilateral leukokoria in the worst cases with traction retinal detachments.
Most common intraocular malignancy in adults.
Rare in black population, but when do occur, are larger, more pigmented and more necrotic.
Predisposition due to: congenital melanosis, ocular melanocytosis, oculodermal melanocytosis, uveral nevi
Are hyperintense on T1 and hypo on T2, which is due to radicals in melanin, therefore related to melanin content.
Amelanotic melanomas have normal MR characteristics of soft tissue (low T1, high T2)
CT: high density, enhance. MR is better.
Choroidal melanoma metastesizes to liver and lung.
Melanoma can also arise in the orbit. Associated wtih nevus of Ota, acular melanocytosis and blue nevi.
Senile macular degeneration
Due to arteriosclerosis. Results in retinal detachment, hemorrhage, gliotic scar in the macular region. Can appear masslike. Pitfall-can be mistaken for melanoma.
A vascular hamartoma in the choroid
Usually present in middle age or older.
2 forms: Circumscribed and diffuse.
Circumscribed is solitary, not associated wtih other things. Can be mistaken for choroid melanoma.
Diffuse angiomatous is associated with Sturge-Weber or facial nevus flameus.
On MR: tend to soft tissue signal, slightly hyperintense on T2
Arises from primite unpigmented epithelium lining oc ciliary body.
Occurs in wide age range. Benign but locally invasive
MR: similar to melanoma.
In children is in differential for retinoblastoma, in adults in differential for melanoma.
Mets to globe
Worst offenders are breast, lung, lymphoma and leukemia.
Often cause eccentric thickening of uveoscleral tim and retrobulbar extension.
Benign tumor of young women
Usually unifocal with ossification. Juxtapapillary location.
CT is best because of the ossification. Punctate calcification in posterior pole of the globe, usually on temporal side of optic nerve.
Differential includes amelanotic melanoma, choroidal hemangioma, metastatic carcinoma, mucinous adenocarcinoma, leukemic o rlymphomatous infiltrates, macular choroidal scars, resoving subretinal hemorrhage.
Occurs in up to 40% of adults iwth a subarachnoid hemorrage, and up to 70% of children.
Is called Terson syndrome if vitreous hemorrhage is also present.
Intraocular hemorrhage can occur with CMV retinitis, meaning immune compromised pts such as HIV.
Ocular hypotony and chroidal detachments
Defined as low tension in the globw secondary to surgery, trauma or glaucoma therapy.
May be observe on CT as uveoscleral infolding (flat tire)
Most often seen after double perforation (a through and through of the globe)
Hypotony of one cause or another (trauma as above, inflammation, meds etc) is the cause of serous chroidal detachment
Hemorrhagic detachment is most common after trauma and has lenticular shape. These do not change location with position.
Serous chroidal efusions are convex and have low density outlined by the detached choroid.
Inflammatory effusions are often due to uveitis and posterior scleritis. These are high density and may change position with head movements
sensory retina is detahced from pigment epithelium
V shape with apex at optic disk
May extend to ora serrata
Associated with retinoblastoma, coats disease, toxocara endophalmitis, diabetes, melanoma, choroidal hemangiomas, subretinal hemorrhage, senile macular degeneration.
Choroidal serrous or hemorrhagic detachments
Choroid is separated from sclera-the subarachnoidal space
Linear or crescent shapes. Can be lenticular.
Only extends so far as the short posterior ciliary arteries and nerves that anchor the choroid to the sclera
Associated with: Ocular hypotony, trauma, surgery, inflammatory choroidal lesions, melanoma
Posterior hyaloid space detachment
Separated posterior hyaloid membrane from sensory retina
Thin semilunar shapes with dependent layering
Associated with macular degeneration, PHPV, Posterior vitreous detachment
Posterior globe configuration changes to look conical like a tent.
Caused by intraorbital mass lesion producing proptosis with techering of the globe by the stretched optic nerve.
Associated with acute trauma, inflammation, carotid cavernous fistula, subperiosteal abscess, hemorrhage into lymphangioma and varix.
Infectious (any type, bacterioal, fungal, viral) or
Autoimmune (usually collagen vascular diseases)
Can be acute or chronic
Imaging: Thickening and enhancement of posterior sclera and uveal layers. Thickening is nodular or diffuse.
Pitfall, nodular thickening can be mistaken for melanoma. DIffuse type mistaked for lymphoma
Acquired defect of the sclera or cornea line with uveal tissue.
Associated with increasing globe size in patients with axial myopia.
Usually on temporal side of the disc.
Can have outward bulging of posterior portion of the globe with uveoscleral thinning.
Can cause proptosis
COngenital defect in any ocular structure. Sporadic. Usually unilateral. There is an autosomal dominant form where most are bilateral.
Classified as typical or atypical depending on location and derivation.
Atypical: Occurs in iris.
Typica is cone shaped nothc that occurs in the inferior medial portion of the globe. Cause by incomplete closure of the choroidal fissure, which can result in elongated or otherwise malformed globe, or ocular cyst at the site of fetal optic fissure closure.
May be associated with orbital cysts, midline craniocerebrofacial clefting including sphenoidal encephalocele, agenesis of corpus, olfactory hypoplasia, cardiac abnormalities, retardation, genital hypoplasia, ear anomalies.
Is part of CHARGE syndrome, also Len's microphthalmia, Meckel syndrome, trisaomy 13, Goldenhar syndrome, Rubinstein-Taybi syndrome, Aicardi syndrome, Waardenburg anophthalmia syndrome.
Imaging: Cone or notch deformity, usually in posterior globe, which may involve the optic nerve. Eversion of postion of the posterior globe may be presents.
Differential includes: buphthalmos, axial myopia, posterior peripapillary staphyloma, and globe trauma
Associated with tuberous sclerosis, NF, vHLdisease.Grows slowly, does not metastasize.
Imaging: Focal region of calcification at the retina on CT.
Pitfall-calcification at retina can be confused with retinoblastoma.
Optic nerve atrophy
End result of many processes. Nerve loses function and normal coloration from loss of vascular supply.
Imaging: MR shows atrophic nerve
Associations: Congenitaloptic nerve hypoplasia, macrophthalmos, compression (pituitary lesions, craniopharyngioma, herpes zoster, MS, trauma, galucoma, ischemic optic neuropathy, toxins, malnutrition
In children concerning of DeMorsier syndrome (septooptic dysplasia)
Optic nerve drusen
Laminated calcareous deposits located in the substance of the optic nerve anterior to the lamina cribrosa.
May form when partially calcified extracellular mirochondria from disrupted exaons serve as substrate for calcium deposition.
May progressively enlarge over years.
2% incidence. May be familial, in which case often bilateral.
Associated with retinitis pigmentosa.
Located at junction of optic nerve and globe.
Imaging: On CT, punctate clacifications at junction of nerve an globe. MR is not good.
Often only identifieable by imaging since the optic nerve surface looks fine to the ophthalmologist
Inflammatory lesion of the optic nerve with pain, decreased vision, abnormal color perception, afferent pupillary defect.
Found in up to 87% of MS sufferers, often as first clinical symptom.
65% of first time sufferes already have WM lesions on MRI.
Other associations: ischemia, vasculitis, satcoid, SLE, Lyme, viral, toxoplasmosis, TB, chemo (cis-platinum), radiation.
Imaging: MR is best. May show T2 hyperintensity of the nerve. Nerve is almost always normal size. Post gado with fat suppression is best sequence to show edema (about 50% of cases) including the intracranial portion.
Optic nerve glioma
Is a juvenile pilocytic astrocytoma. Mean age of presentation is 8.5 when overall, (5 when associated with NF1, 12 without)
Represents 2/3 of pall primary optic nerve tumors.
Optic nerve involvement more common in females. Chiasmal are equal.
Growth phase during childhood, causing them to become symptomatic, then stabilize in most, but indolent progression in 40%
Symptoms: strabismus, visual loss, afferent pupillary defect followed by proptosis.
Decreased vision is an early sign in meningiom, but late in glioma.
10-38% associated with NF1, in which case often bilateral.
1/4 are confined to the infraorbital nerve. 40% extend to hypothalamus (worse morbidity, mortality)
Rare adult type is commonly malignant with intracranial extension. Poor prognosis. Differential: MS, sarcoid, meningioma, hemgioblastoma, lymphoma, leukemia
Imaging: tortuous, enlarge nerve, iso T1 and iso to high T2. Variably enhancing. On CT, enlarged nerve and canal (if it goes that far)
Optic nerve sheath meningioma
Usually form meninges of the nerve, but can extend from cranial meninges.
Clinical: Insidulous loss of vision, optic atrophy, mild proptosis, opticociliary shunts.
Predominance in middle age women and children with NF.
Can be diffuse tubular, fusiform, globular perioptic and nerve may even be separate from tumor mass.
When associtate with NF, also look for pneumosinus dilatans of sphenoid, blisterirn of the planuym sphenoidale.
Calcification is not infrequent (unlike nerve sheath meningioma, which does not calcify)
Imaging: On CT, high density mass with enhancement. Bony erosion or hyperostosis possible. Optic canal usually normal, but can be either enlarged (erosis) or small (hyperostosis). On MR, again enhancement. Same tram tack appearance.
Differential includes hemangioblastoma of optic nerve in vHL, cavernous hemangioma, rarely optic nerve glioma.
Cavernous or capillary. Cavernous is most common primary orbital tumor.
Consis of dilated endoethelial lined vascular channels in a fibrous pesudocapsule.
F>M, Presnts in teens to 40s with slow onset proptosis, visual disturbance.
Grows very slowly and can even stop, but can grow rapidly in pregnancy (hormone dependent?)
Imaging: On Ct, smooth high density round or oval intraconal thing with avid enhancement. On MR, isointense to muscle, hypo to fat on T1. High on T2, again avidly enhancing, patchy at first with total filling by 30 minutes.
Differential: hemangiopericytoma on CT, neurofibroma, schwannoma, benign mesenchymal tumor.
Orbital venous anomalies
No arterial supply on angiography is a must. Can really be venous or lymphatic or even both, but distinction is near impossible.
MR is splotchy due to areas of slow flow and areas of thrombus.
Venous malfomration with dilatation of otherwise normal venous system or abnormal venous channels affecting the superior and/or inferior ophthalmic veins with intermittent proptosis and retrobulbar pain.
Can have a single vessel ar many varicosities.
Proptosis and enlargement of veins brought out by Valsalva maneuver or coughing.
Usually congenital. Also can occur from trauma.
Dysplatic vascular channels (lymph or venous), loose connective tissue and smooth muscle. Really a type of hamartoma.
Generally extraconal, may be posterior or anterior, but have been found just about anywhere.
Not well encapsulated.
Peak presentation at 23 years with range from newborn to decrepit.
Tendency to hemorrhage bringing about acute onset of symptoms.
Imaging: On CT orbital expansion, irregular margins crossing anatomic boundaries, high density, variable enhancement. Can have calcified phleboliths. On MR, heterogeneous appearance of cysts due to hemorrhage.
Carotid cavernous fistula
Direct communication between intracavernous portion carotid to venous cavernous sinus.
Most common cuase is severe trauma. Alos spontaneous rupture of aneurysm.
Clinical: pulsatin exophthalmos, orbital bruit, motility disturbance with dilated conjunctival vessels and glaucoma.
Causes enlargement of extraocular muscles, proptosis, dilation of the superior ophthalmic vein (unilateral, as oppsed to bilateral in case of diffuse cerebral swelling)
Conjunctival edema causes periorbital swelling and blurring of globe margin.
On Angio-direct communication of cavernous carotid to cavernous sinus and filling of other venous structures including ophthalmic veins, petrosal sinuses, cortical veins. This is often bilateral through intercavernous connections.
Spontaneous fistula associated with Osteogenesis imprefecta, Ehlers-Danlos, Pseudoxanthoma elasticum.
Cavernous sinus dural malformations
Not usually traumatic in origin. Instead linked to venous thrombosis.
Symtpoms less fulminant. Can have periocular pain. 3,4,6 nerve palsies, visula loss (6th nerve due to compression of Dorello canal)
Common cause of unilateral exophthalmos (contrast to grave, which is mostly bilateral)
Clinical: Restricted motion, chemosis, lid swelling, pain. Onset is rapid. Symptoms respond to steroids (except the chronic form, that doesn't, use chemo or radiation)
Thought to be autoimmune involving the lacrimal gland, sac or extraocular muscles etc.
Can extend intracranially.
Contour of involved muscles may not be smooth (graves is always smooth) and may affect the insertions.
Imaging: can be a lacrimal mass, ill-defined retrobulbar mass, or just thick muscles/tendons/sheaths. 70% have proptosis. Subtle dirty orbital fat.
Associated with Wegener, polyarteritis nodosa, sarcoidosis, SLE, Dermatomyositis, RA etc. Also retroperitoneal fibrosis, sclerosing cholangitis, Riedel thyroiditis, nediastinal fibrosis. This actually only about 10% of cases.
Can occur before during or after treatment.
On CT, prominent extraocular muscle enlargment and proptosis (start in inferior then goes around heading medial first.) Enlargement of all muscles is the most common pattern. Includes the tensor intermuscularis muscle.
85% bilateral, only 5% unilatera, the remainder being normal.
Orbital fat may be increased (8% just fat increase alone). 46% muscle and fat both involved.
Optic nerve thickening and bony erosion can occur late in the process.
Clinically look for lid lag, diplopia, limited movement, proptosis, optic nerve compression due to periorbital fibrosis.
Common, up to 25% of all sarcoid cases, but isolated orbital disease is rare, usually in lacrymal glands
Most common manifestation is uveitis.
Granulomatous inflmmation, tissue necrosis, vasculitis involving arteries and veins.
May extend from sinuses or be primary in orbit.
Up to 54% of Wegener cases have neurologic involvement, half of these in the orbit.
Most common ocular manifestation is keratitis and scleritis.
Orbital involvement usually late, produces pain, proptosis, erythematous eyelid edema, limited movement.
Imaging: On MR, hypointense relative to orbital fat on T2. Homogeneous enhancement. Classically with associated sinus disease and bone destruction. Anterior segment usually more often than posterior.
Most common neurologic involvement is peripheral neuropathy, particularly mononeuropathy multiplex.
Differential: Poluarteritis nodosa, lypmphomatoid granulomatosis, behcet;s, primary vasculitis, lymphopropliferative disorders, sarcoid, churg-strauss, erdenheim-chester disease. Ahything with leptomeningeal enhancement and ophthalmic and neurologic involvement.
Can be primary orbital, or extension from systemic.
Generally in older population.
Presents with slow, progressive painless periorbital swelling and low grade proptosis.
On CT, diffuse infiltratetive mass destroying orbital architecture.
If globe is invaded, may show decreased density on precontrast images.
Appears similar to diffuse pseudotumor.
Tendency for superior location in orbit. Does not usually extend beyong orbit. Bone destruction rare.
Most often involved superior rectus.
PTLD in orbit
Common location for PTLD.
Soft tissue mass with propensity for lactimal region with contrast enhancement.
Agressive bone destruction is common (contrrast with lymphoma which molds to orbit)
Painless swelling and erythema of sking and subcutaneous soft tissues
No proptosis, disturbance of movement or chemosis
No abnormality posterior to orbital septum on CT and MRI. Medical treatment
Located within the bony orbit, beneath the orbital septum.
Presents with painful ophthalmoplegia, proptosis, chemosis, decreasisng vision.
Edema and inflammation without discrete abscess formation within orbit.
Common cuases: sinus infection, bacteremia, skin infection, foreign body.
CT is better than MRI, cause can seen the sinuses well and foreign bodies.
Can produce venous thrombosis of orbital veins with ectension into cavernous sinus. Therefore important to image brain as well, since intracranial complication has 50-80% mortality rate.
Granulomatous disease endemic in africa, asia, south america, eastern europe. Cause is Klebsiela rhinoscleromatis.
Starts in sinuses, but then can extend to lacrimal sca and orbits.
On MRI, intermediate intesity on T1, low on T2. Enhances. Similar appearance to malignant tumors and fungal sinusitis
Expansile mass occuring after obstruction of sinus ostia. Presents with diplopia and proptosis if extends into or near orbit.
Most common location is frontal sinus and ethmoid sinusThere is bowing and thinning of bone without brekthrough.
Variable intensity on MRI due to variable contents.
Most common congenital lesion in orbit
Usually present in first decade, but has large range.
Can rupture, causing granulomatous reaction and scarring.
Most often located in superolateral portion of the orbit at frontozygomatic suture near the lactimal fossa.
Most common primary malignant orbital tumor of chilhood
Also orbit is the most coomon site of head/nck rhabdomyosarcoma.
Presentation mean at 7/8 years. 90% before age 16.
Clinical: May be palpable, echymosis, conjunctival chemosis, ophthalmoplegia.
Primary tumor arises from primitive orbital mesenchumal elements. Secondary involvement is by extension from extraocular muscles, nasopharynx, paranasal sinuses.
Imaging: On CT, iso or slighlty high density with uniform enhancement. Usually located behind globe (50%) or above (25%). Homogeneous, well defined.
Orbital fibrous histiocytoma
onloy 1% of primary tumors here, but still most common primary orbital mesenchymal tumor in adults (whatever)
Mostly benign, but can be locally aggressive.
Presentation with possibly palpable mass, proptosis, diplopia. Age usualy 40s-50s. Usually discrete, smooth mass. Intra or extraconal. Usually enhance.
Most are extraconal, but invade with enlargement or compress the cone.
Average survivial after presentation is 9 months, so a late, bad finding.
Usually present with diplopia, ptosis, proptosis, eyelid swelling, pain, visual loss.
Greater wing of sphenoid is the common site of bone mets.
On CT, isodense or hyperdense, may enhance,
Breast and lung cancers make up 50% of mets to orbit. Breast supposedly initially involves the fat.
Thyroid, carcinoid, renal cell tend to produce discrete nodules, others become diffuse.
Metastatic neuroblastoma is second most common malignant orbital tumor of childhood.
HIgh density and lack of preseptal extension (as opposed to rhabromyosarcoma)
Contents: Pterygopalatine ganglia (of V2), pterygopalatine plexus
Anatomy of cavernous sinus
Subdivided into intracavernous and interdural compartments.
Tumors that arise interdurraly (within the lateral wall) have smooth contours, oval shape, displace intracavernous partion of internal carotid without encasement or narrowing. Compress but do not obliterate the sinus
Intracavernous lesiosn encase and narrow the ICA and can obliterate the sinus.
Drains into superior and inferior pterosal sinuses.
Basilat venous plexus in the dura behindclivus provides lots of other connections.
Makes the lateral wall of the sella.
men <= 8 mm high
women <= 9mm
Children <12 <= 6 mm
upper surface flat or slightly concave.
Can increase in pregnancy, becoming slighly convex, still no more than 10mm and up to 12 mm in postpartum period.
Shrinks after 50 or so
Anterior is iso to brain, posterior bright on T1
In infants, anterior can be higher intensity, and posterior bright spot may be absent
Posterior bright spot may also be absent in diabetes insipidus.
Enhances within seconds, then washes out slowly over 20-30 minutes
Congenital abnormalities: Aplasioa, hypoplasiam duplication. Occur alone or with long list of other syndromes incluidng CHARGE, septooptic dysplasia, anencephaly among others.
Usually <10 mm. Usually hypointense to normal glnad on T1. Variable on T2. Hypoenhancing initially, but after 20 minute washout the gland washes out and the tumor does not, appearing hyperintense
The adenoma can actually arise in the infundibulum and the extend down or up.
Serum prolactin is usually presenting symptoms (>200 is highly specific and >1000 implies cavernous sinus invasion).
Only about 75 have hormonal abnormality though.
Usually picked up so large because they are not functioning, or only low functioning. Often present with ocular distubances (bitemporal hemianopsia)
Have a propensity for hemorrhage and infarction due to tenuous blood supply, therefore appearing highly heterogeneous on MRI. Bromocryptine apparently increases chance of hemorrhage.
Most common ectopic location is suprasellar cistern, often continuous with the stalk (getting back to originating in the infundibulum)
Associated with McCUne-Albright syndrome
Pitfall: Can be confused with craniopharyngioma or Rathke's cleft cyst sue to location and hemorrhage.
Sudden infarct of the piptuitary gland.
Symptoms appear very suddenly: Ophthalmoplegia, headache, visual loss, vomiting.
Can be due to infarction or hemorrhage. MRI is good either way (DWI vs T1/T2/GRE)
Pituitary hemorrhage for some reason not associated with hemosiderin deposition.
Association to Korean hemorrhagic fever (hantaa virus), which cases pituitary necrosis or atrophy with visual field defects.
Make up 1.8-12% of pituitary lesions
Breast most common then
Often clinically silent, picked up incidentally.
Inflammatory disease of the pituitary involving the infundibulum.
Seen most often in young women in late pregnancy or postpartum. More rarely seen in men (in which case more commonly invoving the hypothalamus)
Pituitary and stalk are diffusely enlarged and enhancing. Normal stalk is 2 mm. In hypophysitis commonly 4 mm or more, up to 1 cm or so.
Can be associated with deranged hormone levels, including dibetes insupidus.
Pinching of stalk by tight diaphragma sella may compromise blood supply to posterior pituitary. Bright spot is often gone.
Posterior pituitary tumors
Chorisotoma is a glangular cell tumor that may propduce visual or endocrine disturbance. Variable on T1, T2 and PDW and enhance.
Sagittal imaging is key to actually localize it to the posterior pituitary.
Can also occur in suprasellar and third ventricle.
May be vascular, so important to diagnose to avoid surprises at surgery.
Other sellar oddities
Intrasellar meningioma-enhances brightly like others. Can simulate a pituitary mass. Suggested by a readily identified diaphragma sella. Look for a dural tail and slightly different signal than pituitary proper
Intrasellar carotid aneurysm- can produce sellar enlargement and mass effect. Also 50% of persistent trigeminal artery go through sella-another possible surgical surprise-important to diagnose.
A form of dwarfism due to low levels of growth hormone.
There is often a finding of atrophy or even truncation of the infunfibulum (truncation is the more common) if there is completely isolated GH deficiency, and the adenohypophysis is normal or small.
Associated ectopic posterior pituitary is common.
When there are multiple hormonal deficiencies, there is association to small or absent anterior pituitary and stalk. The neurohypophsysis is either altogether gone or ectopic.
Subgroup of hereditary GH deficiency, who are unable to synthesize the stuff actually have a normal pituitary-hypothalamic axis.
Stalk should not be larger than the basilar artery
Enlarged infundibulum can be due to granulomatous disease (langerhans, sarcoid, TB, Erdheim-Chester) often also extending into hypothalamus. These are often isointense. Differential for this is chiasmatic/hypothoalamic glioma.
Other infundibular lesions: Mets, lymphoma, germinoma, craniopharyngioma, cleft cyst, prolactinoma.
Diabetes insipidus is common association of any pituitary/stalk lesions
May be seen in children or adults.
More than 50% are in adults, but in children account for a greater percentage of tumors.
Usually arise suprosellar (90%), can be infrasellar. Arises from remnant of Rathke's pouch.
Can extend into any cranial fossa, retroclival region, lateral ventricles.
Can rarely arise in 3rd ventricle, sphenoid bone, nesopharynx, cerebellopontine angle and pineal gland (all places with rests of extopic pituitary cells).
Rule: if you see a bizarre tumore with a skull base component, probably a craniopharyngioma.
Palisading adamantinous epithelium, calcifications, keratin nodules.
Squamous papillary variety does not calcify, is solid, occuring mostly in adults.
Imaging Hallmarks: Calcification (rim or nodular, 80%), Cyst formation (85%), Enhancement (solid or nodular)
MRI: ranges from hypo to hyper on T1. High on T2. High T1 due to methemoglobin or high protein.
Intraventricular location is atypical. These do not extend below 3rd ventricle, mostly in adults and male preponderance. Hormonal derangement is rare. Low incidence of cysts and calcification (in other words, everything that cranyopharyngioma usually is not). Uniform enhancement.
Mass lesion in suprasellar cistern.
T1 iso to brain, high on T2.
Calcification rare unless post radiation.
High T2 cystic component can be seen.
Bilateral optic nerve astrocytomas associated with NF.
Hypothalamic astrocytomas and gangliogliomas hard to distinguish from chiasmatic. If chiasm is normal, but floor of third ventricle abnormal, likely hypothalamic.
Optic radiations are not involved.
Tuber Cinereum Hamartoma
Cause central precocious puberty and gelastic seizures. Mechanism is secretion of leutenizing-hormone releasing hormone by the hamartoma. Seizure mechanism is from connection of the hamartoma to limbic system or brain abnormalities.
Congenital and non-neoplastic.
Look for abnormal signal just anterior to mamillary bodies (iso to gray on T1, hyper on PDW and T2) and no enhancement.
May be pedunculated
Also do not calcify, contain fat or cysts (since its normal tissue in wrong location)
Age range: children and young adults
Variable presentation: diabetes insipidus common, hypopituitarism, optic chiasm complression.
Arise from primitive germ cells.
Mass lesions can be locally invasice.
CT: High density, uniformy enhancing-similar to lymphoma. Do not calcify.
May coexist with a proper pineal lesion.
Mets by subarachnoid seeding.
Nasopalatine duct cyst
NPDC aka incisive canal cyst
often an incidental benign finding in the maxilla seen on CT or MRI, and is usually asymptomatic unless secondarily infected.
Surgical enucleation is the treatment of choice
Is the most common cyst of nonodontogenic origin in the maxilla
Likely remnants of the embryonic nasopalatine duct
Common in the fourth to sixth decade of life with a slight male predominance
Imaging: well-defined round, oval, or heart-shaped cyst and is found in the midline of the anterior maxilla. Must be over 6 mm diameter (which is the max size of a normal incisive foramen cyst). Homogenous high signal on T1 and T2. Does not enhance.
If the cyst preferentially extends anteriorly it is termed a median alveolar cyst, and if it extends posteriorly it is termed a median palatal cyst.
VLCS is a common cause of unilateral trigeminal neuralgia, a clinical syndrome composed of paroxysmal facial pain usually confined to the maxillary (V2) and/or mandibular (V3) branches of the trigeminal nerve.
Age usually over 65, no sex preference.
Imaging: Vessel courses into the anterior cerebellopontine cistern with subsequent irritation of the 5th cranial nerve at the preganglionic root entry zone (REnZ).
High resolution T2 MRI shows a serpiginous asymmetric signal void (vessel) in the ipsilateral CPA.
Most common vessel is superior celebellar artery, followed by PICA.
Treatment of choice is microvascular decompression with 70% of patient's pain free on no medication 10 years later.
Cavernous sinus thrombosis
Associated with sepsis or with dural malformations. Also from surgical or interventional procedure.
Imaging: may see high intensity int he occluded sinus. Often the sinus is only partially occluded. No use looking at enhancement since the non-thrombosed areas are filled with blood, and also enhance vividly.
Look for enlarged ophthalmic vein, preiorbital swelling or thickening of extraocular muscles.
Cavernaous sinus Meningioma
Including this because they are slighly different from the rest.
Follow lateral margin of the sinus, may extend along tentorial margin posteriorly "dove's tail"
Bulge the lateral margin of the sinus.
Arise from intracranial portion of trigeminal nerve.
Based predominanly in the middle cranial fossa, region of gasserian ganglion (sits in meckel's cave) or posterior fossa. Can be dumbbell shaped (least common).
Peak incidence is 30s.
Most frequent symptom is trigeminal nerve dysfuction, including pain, numbness and paresthesias
Imaging: on MR, this is a smooth mass, iso on T1, and high on T2. Enhances vividly. Cystic change may occur. May grow through neural foramina producing smooth enlargement. Can be traced along the nerves from pons, prepontine cistern and gasserian ganglia into cavernous sinus.
On Ct, can see erosion of petrous of bone, particularly petrous apex where the nerve passes.
Benign tumor that arises from the leptomeninges. (the other end of the spectrum is meningeal melanoma)
Can occur in cavernous sinus and Meckel's cave among othe places.
Imaging: Hyperdense. High T1, low T2. Do not enhance.
Perinerual spread of head and neck tumors and infection
There are many tumors and infections that spread along head and neck nerves into the base of the skull.
CN V is most commonly involved due to its extensive supply of the head and neck region.
Imaging: look for thickening of CN V or other CN nerves and branches., Concentric enlargement of the foramen ovale (in the case of CN V), replacment of normal CSF density and intensity in the trugeminal cistern (Meckels cave), a mass in the cavernous sinus, atrophy of the ipsilateral masticator muscles.
Skull base chondrosarcoma
Most occur from teens to 30s.
Symptoms are location dependend. Most will have had headaches and intermittent cranial nerve palsies (particularly IV).
On plain skull film can see stippled calcificationamorphous or ringlike calcification, but can be pure lytic also.
Locations: Parasellar, cerebellopontine angle, frontal convexity.
Associated with Mafucci syndrome
On CT, calcified mass with markedly enhancing neoplastic tissue.
Prototypic patient is a young male.
Most common benign tumor of the nasopharynx, most originating in the posterior lateral wall of the nasal cavity.
Often grow through the pterygopalatine foramina and may extend into the infratemporal fossa.
Can cause severe epistaxis, nasal obstruction, facial deformity.
Extremely vascular, may see flow voids on MR, also because of this strongly enhancing.
Best modality is Angio, which shows a dense tumor blush. Also good time to do preoperative embolization that will control bleeding for surgical resection.
Occurs at sites of notochordal remnants, faily rare.
There are two peak location, at the skull base (35-40%) and sacrum (50%)
Age peaks are different, 20-40 for skull base and 40-60 for sacrum.
About 15% are spinal.
In the skall base most common location is the clivus.
Benign, but can be aggressive and extensive.
Patients present with headache, visual disturbances, cranial nerve palsies of variable duration, possibly waxing and waning.
Imaging: Soft tissue mass, bone destruction, calcification (about 50%). Hihg T2 intensity on MR. Most enhance.
Congenital malformations of the EAC
Are mor common than of the innter ear.
Minor microtia-pocket ear, absence of upper helix, tragus, etc. 50% of patients also have dysplastic malleus-incus complex
Major microtia, 67% have associated dysplasia and 30% are completely absent.
Stapes abnormalities present in up to 70%.
There was a large spike abnormalities in 1960s due to thalidomide. Currently Rubella accounts for some.
EAC atresia is bilateral in about 1/4 cases. Microtia coexists in 73%. In EAC atresia, horizontal portion of facial nerve may have abberant course.
Association tu abnormal temporomandibular joint (mandibular consyle and EAC develop from the same branchial apparatus.) Zygomatic arch can also be involved
Keratinous plugs and cholesteatomas may form.
Association to inner ear abnormality can happen, but rare, because developmental origin is different (neuroectoderm)
Malignant otitis externa
Most severe inflammatory condition affecting the EAC.
Is caused by Psudomonas infection.
Prototypic patient is elderly and diabetic.
Presents with foul smelling purulent dicharge. Can have CN palsies, particularly VI, VII, IX, XII
Starts at junction of bony and cartilaginous portionn of EAC, along fissures of Santorini
Activity on gallium citrate scan.
Plugs of keratin in EAS
Hard to distinguish from cholesteatoma on imaging.
Keratosis is painful, usually bilateral, in middle age adults with histories of bronchiectasis or sinusitis.
Cholesteatomas are unilateral, seen in older patients, with less severe pain and more bone erosion
Benign tumors of external ear
Minor solivary gland tumor
Congenital abnormalities of the middle ear
may coexist with abnormalities of the facial nerve
Not as common as abnormalities of the external ear.
When isolated, distal incus long procees and stapes are most commonly affected, followed by stapes alone and incus alone. These two are from the 2nd branchial arch (malleus and incus short process are from 1st arch)
Skull base epidermoid
This is just the more technical term for an acquired cholesteatoma.
Classic location is the petrous apex along Korner's septum, in the mastoid air cells, the Eustacian tube opening, Geniculate ganglion region, mddle ear-tympanum junction.
Pearly white to naked eye.
Imaging: hypo on T1 (but higher than CSF), bright as CSF on T2.Present with loss of hearning, vertigo, facial nerve palsy.
Scutum is usually intact.
Do not enhance.
There is opacification of the epitympanic recess with thickening of the tympanic membrane.
Most are due to strep, Moraxella catarrhalis, H influenzae, pneumococcus.
In children, obstruction of the eustachian tube outlet can lead to otitis media.
Ossicular erosion is a rare complication, which in itself is a marker for acquired cholesteatoma. Mostly effects the long process of the incus, leading to conductive hearing loss. On CT, look like punched out holes in the ossicles.
Dislocation of ossicles
Can be caused by trauma or infection.
Suspect when there is more than 1 mm distance between long process o fincus and the head of the stapes.
Incudal disarticulation accounts for more tha 80% of post-traumatic consuctive hearing loss.
Infection introduced from middle ear via the aditus ad antrum, the channed connecting the middle ear to mastoid antrum
Therefore can occur as complication of otitis media.
Long-standing endotracheal tube is a predisposing factor.
Coalescence in mastoid is poor sign, since it represents bone infection.COmplications include sigmoid sinus thrombosis, thrombophlebitis, epidural abscess, meningitis, subperitoneal abscess, fistulas, Bezhold's abscess and osteomyelitis.
Usual organisms are beta hemolytic strep and penumococci.
Imgaing: Very bright on T2. Can sometime ssee air-fluid level, but usually just opacification. Look for middle ear involvement.
Results from recurrent otomastoiditis (such as may occur from eustacian tube dysfunction)
Represents an erosive collection of kerainous debris from ingrowth of stratified squamous epithelium through a perforated tympanic membrane. Critical features include presence of bone erosion and or expansion.
Most often arises from a peforation in the pars flaccida of the tympanic membrane. Extends into Prussak's space, then through the aditus ad antrum into mastoid air cells.
Imaging: Hypo on T1 and intermediate on T2. They do not enhance.
Both types of cholesteatomas can result in fisulas into semicircular canals (lateral most common), may erode the tegmen tympani and invade the intracranial compartment. Also can erode the lateral or inferior wall of facial nerve tympanic portion.
Pars tensa cholesteatoma
Much less common than the acquired pars flacida ones. Usually arise from perforation posterosuperior-most portion. Then expand to sinus tympani, pyramidal eminence and facial recess.
Present with mass in middle ear, erosion of the long process of the incus or spates, epiympanic spread and ossicular displacement.
Scutum usually intact.
Both types of cholesteatomas can result in fisulas into semicircular canals (lateral most common), may erode the tegmen tympani and invade the intracranial compartment. Also can erode the lateral or inferior wall of facial nerve tympanic portion.
A variant of the glomus tumor, this one occuring in the ear. Arises from paraganglioma tissue in the middle ear.
Presents with pulsatile tinnitis. Usually small on presentation due to early symptoms. Usually along the lateral aspect of the cochlea in the middle ear cavity.
Most common neoplasm in the inferior part of the middle ear.
Prototypical patient is a middle-age female.
Imaging:Like all glomus tumors, enhances vividly.
Persistent stapedial artery
Rare, <0.5% incidence
Embryologically is a branch of the hyoid artery, which is itself derived from the 2nd aortic arch. It connects the external and internal carotid artery.
When persists, is a pulsatiel middle ear mass.
Subsumes the role of the middle meningeal artery, so there is an absence of foramen spinosum, soft tissue mass along horizontal portion of the tympanic facial nerve and additional brnach leading from the petrous carotid artery.
Enters middle ear to create the obturator foramen of the stapes. Leaves near the geniculate ganglion.
Associated with abberant internal carotid, trisomy 13, 15, 21, thalidomide, anencephaly and NF
A paraganglioma arising from tissue in the jugular vein near the jugular foramen.
Imaging: Salt and pepper on T1 and T2, due to flow voids in the tumor substance. On CT, erodes the jugular foramen.
May cause pulsatile tinnitus.
Multiple in 15% of cases.
May secrete norepinephrine, so use alpha blocker prior to iodinated contrast or any procedure.
Dural vascular malformations
Commonly affect the transverse sinus and in some cases may be due to previously thrombosed veins or sinuses.
Most common neurologic cause of subjective pulsatile tinnitus is pseudotumor cerebri
Facial nerve schwannomas
Can arise in IAC, labyrinthine portion of the nerve, tympanic portion, geniculate ganglion, mastoid portion or in the parotid gland.
If there is expansion of the facial nerve canal, just assume schwannoma.
Can not be accurately separated from other regional lesions such as vestibular schwannoma in IAC, glomus tumors in tympanic cavity etc.
Can occur in IAC, around geniculate ganglion, posterior genu of the facial nerve canal.
Bone erosion with soft tissue mass seen on CT. May have honeycomb trabeculation inside of the ossifying type.
Distinguished from schwannomas only when there is extensive calcification or when there is enhancement.
Wothout calcification also think glomus tympanicum.
Malignant lesions in the middle ear
Usually arise from EAC structures which then invade the middle ear.
Think squamous cell carcinoma, rhabdomyosarcoma (by extension or primary), salivary gland tumors from extopic rests (adeno, adenoid cystic carcinoma).
Inner ear congenital abnormalities
Structure develop 4th-10th weeks.
Mondini defect is most common.
Cock's deformity is second most common
Also cochlear aplasia and hypoplasia, where cochlea may fail to form at all.
Cochlear aqueduct congenital enlargement may result in hearing defect.
Medial orifice size of more than 1.5 mm or midportion diameter moare than 1.2 mm is abnormal.
Abnormal connection between the subarachnoid space and the perilympnatic space of the inner ear.
Usual sites in children are at the oval and round windows, often associated wtih stapes malformations.
Fistula can provide easy tract for spread of middle ear infections to meninges.
Congenital causes include vestibular aqueduct enlargement, Mondini, Michel's and Cock's deformities.
Acquired causes include cholesteatomas, chronic otitis media and trauma
Semicircular canal abnormalities
Lateral is most often effected in form of hypoplasia, because it is the last to form (superior is first).
This somehow results in hearing loss rather than balance problems.
An isolated semicircular canal defect implies the problem in week 8-9
Associated with CHARGE syndrome.
Superior semicircular canal dehiscence is characterized by sound and or pressure induced vertigo (Tulio phenomenon)
Vestibular aqueduct abnormalities
Flaring of vestibular aqueduct over 1.5 mm is enlarged vestibular aqueduct syndrome. This is most common cause of congenital sensorineural hearing loss.
Also seen after trauma.
Midpoint of normal duct should have diameter to 1.5 mm or less.
Enlarged vestibular aqueduct causes high frequency hearing loss. May be isolated o associated with abnormal cochlea (76%), Cystic vetibules (31%), abnormal semicircular canals (23%)
May also have nelarged endolymphatic sac, which is brighter than CSF on T1 due to high protein. Also associated with Penred, Congenital CMV infection, defects in modiolus of the cochlea.
Also can be narrowed as in Meniere (<0.5mm)
Atresia is associated with absence of CN VIII and VII
congenital anomaly that is a manifestation of the split notochord syndrome.
most commonly found in the cervical region and typically extend over three segments.
Most are intradural, extramedullary, and ventral to the spinal cord.
may also be intramedullary or extradural.
frequently associated with vertebral abnormalities, including spina bifida.
Result from persistent patency of the notochordal canal (canal of Kovalevsky) with a consequent communication between the gut and the dorsal skin collectively grouped under the term of split notochord syndrome.
Associated to vertebral anomalies such as hemi- or butterfly vertebrae and may display an extraspinal component, located in the mesentery or mediastinum
Semicircular canal abnormalities
A form of otic dysplasia.
Order if cana development is Superior, Anterior then Lateral.
The lateral canal is last formed and Most often involved. If the anterior canal is malformed, the alteral is almost always also involved.
There is compensatory enlargement of the vestibule.
Symptoms is heaering loss, not inbalance.
This is an isolated problem with the canals without cochlear involvement, and is due to insult after 8-9 weeks gestation age.
Associated with CHARGE
Superior semicirculat canal dehiscence
Presenting symptom is vertigo induced by sound or pressure
Oscillopsia and lound noise induced vertigo.
Occurs in otosyphillis, Meniere disease, Perilymphatic fistula, Lyme disease.
Vestibular aqueductal abnormality
Defined as diameter greater than 1.5-2.0 mm
Is the MOST common cause of congenital sensoryneural hearing loss
Can also occur after trauma
The midpoint of the duct should be 1.5 mm or less
Enlarged canal causes high frequency hearing loss.
Can be associated with cochlear abnormality (76%), cystic vestibule (31%), abnormal semicircular canals (23%).
The dilated endolypmphatic sac may have signal greater than CSF on T2 2/2 increased protein.
Has association with Pendred syndrome
Genetic syndrome associated with severe hearing loss and abnormalities of the inner ear including enlarged vestibular aqueduct and modiolus defect
The normal vestibular aqueduct should be no lass than 0.5 mm.
Aqueduct narrowing is associated with Meniere disease.
Atresia or stenosis of internal acoustic canal
Is associated with absence of CN VIII more so than CN VII
Hearing loss patient is candidate for implant, therefore finding an intact nerve is important, necessitating high res MRI.
Syndromes associated with inner ear abnormalities
Treacher Collins syndrome
Occurs after chronic middle ear infection, traumea, cholesteatoma, bacterial meningitis, mumps, Cogan's syndrome, lanyrinthectomy
Fibroblasts are induced, then osteoblasts, resulting in deafness and/or vertigo
Imaging: ~40% have cochlear stenosis. There is cochlear fibro-ossific change. Obliteration is not uncommon in semicircular canals and vetibule.
Is defined as replacement of enchondral bone by spongy bone.
A cause of bilateral sensorineural hearing loss, ~80% of cases.
Occurst MOST frequentlyl in young to middle age women
Imaging: earliest seen is a lucent lytic erosion of labyrinth margin of the oval window and cochlea.
Fenestral type (aka retrocochlear) affect the anterior margin.
Cochlear form affects middle and basal turns most often. "Double ring" sign around membranous cochlea
Cochlear deminiralization in a child
Can be seen in
Causes of labyrinthine ossification
Cholesteotoma with labirinthine fistula
Chronic otitis media
Late or treated otospongiosis
A more common form than the cochlear type
Affects oval window (80-90%) more than round window (30-50%)
Bilateral in 85% of cases
Predominantly occurs in young patients (70% are 18-30)
The stapes is stuck to the oval window in a position preventing sound trasmission = conductive hearing loss.
Both spongiosis and plaques narrow the round windown niche
Treatment: Surgical, small fenestral stapedectomy or total stapedectomy with prosthesis.
Defined as Endolymphatic hydrops
Imaging: can not see endolypphatic sac in high res 3d T2 images.
Paget's disease involvement of inner ear
Can result in sensorineural or conductive loss depending on the exact affected bone
With regard to inner ear structure, Paget's tends to involve from perifery moving centrally, as compared on cochlear otosclerosis which follows the reverse course, central to peripheral.
Often presents as sudden hearing loss and vertigo, often unilateral.
There is an autoimmune type, which is usually bilateral.
Imaging: Cochelar enhances. May also see inhancement of labyrinth apparatus.
When asymptomatic, there is also no enhancement.
Diff: Labyrithine schwannoma
Dense temporal bones
Congenital hypoplasia of the mastoid
A nondestructive inflammatory condition of the aerated petrous apex.
The apex is pneumatized in the first place in only 30% of population.
Often happens after "successful" resection of mastoid for inflammatory disease.
Associated with Gradenigo's syndrome
Imaging: Opacification of the petrous air cells with decreased T1 signal and increased T2 signal. The dura near Meckels' cave may enhance.
CN VI may be affected in Dorello's canal.
Typically arises in the petrous apex.
The cause is thought to be rupture of a small vessel with recurrent hemorrhage intot he apex, which elicits a foreign body response with giant cell and fibroblastic choanges and cholestrol crystal collections.
The lesions expands until CN V or CN VIII symptoms cause the patient to present.
THIS IS NOT A CHOLESTEATOMA
Imaging: Increased signal on all sequences (vs cholesteatoma which has decreased T1 signal)
Enhancement is periferal (like a mucocele)
Differential: Mucocele of apex, petrous apicitis, hemorrhagic bony mets.
Pitfall: Apical fat and granuloma both have increased T1 and T2 signal of FSE. Look for bony expansion to confirm granuloma diagnosis.
Endolymphatic sac tumors
Specifically defined as tumor of endolymphatic sac origin
These arise from the jugular bulb, mucosa of aerated cells nearby.
Imaging: They are agressive, with bony destruction, calcific matric on CT. Bright T1 signal when small, and possible flow voids when over 2 cm.
Associated with vHL syndrome.
Can look like the vestibular aqueduct.
Note: Schwannoma of the IAC is far more common for unilateral hearing loss than ELST.
Vertical temporal bone fracture
Vertical fracture is only about 1/5 as common as horizontal.
Divided into lateral and medial. Lateral goes through the cochlea. Medial through the IAC.
CN VIII is damaged in about 40% and hemotympamum seen in about 50%
Horizontal temporal bone fracture
Traverses the EAC, middle ear and often sphenoid bone.
15-20% are associtated with ossicular dislocation
90% rate of hemotympanum (compare with only 50 for vertical fracture)
Otorrhea seen in about 50%
Always look for air fluid levels in the mastoid and middle ear as sign of sublte fracture.
Develoment of the frontal sinus
Pneumatises around age 1-2 years.
Growth posteriorly over orbital roof occurs from about 4 to 8 years. Therefore frontal sinusitis is not possible before age 4 .
Development of ethmoid sinuses
Present at birth and expand rapdly up to ~4 years of age, followed by a growth spurt at ~8-12 yrs. These sinuses are the usual source of sinusitis in the young child.
Development of maxillary sinuses
The antrum is present at birth, and there is progressive growth up to ~14 years age.
Development of sphenoid sinuses
Starts developing at ~ age 2 and grows slowly
Overall order of paranasal sinus development
Ethmoid - Maxillary - Frontal - Sphenoid
Presents as respiratory distress while feeding
Membranous atresia accounts for 15%, bony for the rest.
Association with congenital CNS malformation in about 50% cases.
Normal opening should be 0.5 square cm or more in neanonate, 1 cm or more in adolescent.
The vomer should be .34 cm or less in a child less then 8 years old.
Entities that may have choanal atresia
Amnioti band syndrome
Fetal alcohol syndrome
Treacher Collings syndrome
Is not a neoplasm, rather a congenital vascular anomaly.
Is actually more commonly found extranasal.
The soft tissue component is isointense to brain, but has not connection ot the brain.
Treated with surgical excision.
Hypoplastic maxillary antrum
The antral roof is downloaping, with an elarged ipsilateral nasal cavity, low ipsilateral orbital floor and thick lateral antral wall
About 9% frequency in population.
Differential: Silen sinus syndrome
Associations of maxillary expansion
Dyke Davidodd Mason syndrome
Pneumosinus diletans from meningioma
Occasionally bacterial superinfection of sinusitis, esp if chronic
Fungal calcification tend to be central, fine and punctate with HU over 2000. Calcs that are peripheral and eggshell-like are usually not fungal
Is a granulomatous mass-like infection secondary to klebsiella rhinoscleromatis gm - bacteria
Patients usually young.
May result in obstruction of osteomeatal complex leading to obstructive sinusitis.
Ultimately there is sclerosis of the inflamed regions with chronic nasal occlusion.
Inflammation is usually bilateral in anterior and posteior nares.
Imaging: T1/T2 bright signal in inflammatory phase.
Differential: Fungal infection or melanoma.
Entities leading to septal perforation
Forign body reaction
Propensity to invade orbits, cavernous sinus and other neurovascular structures. Particularly Mucor requires wide excision and IV antifungals.
Look forperiantral soft tissue infiltration anterior or posterior to the maxillary sinus in the proper clinical setting
Aspergilus can make polyps or fungus balls which are dense on CT. This can be excised or treated with steroids.
Allergic fungal sinusitis
Is an allergic reaction to fungal infection, much milder than fungal sinusitis.
There is invreased CT density in the sinus, which is decreased density on T2.
In a child the triad of bulging lateral nasal wall, ethmoid opacification and frontal sinus hypoplasia is highly suggestive of CF.
High density secretions may also be seen as well as severe hypoplasia of the sphenoid.
Question CF diagnosis if there is pneumatization.
Polyposis of sinuses
Allergic or hyperplastic
Can be associated with agressive bony destruction
Most cases are bilateral (>80%)
Occurs in 1.3% of general population and 16% of chronic sinusitis sufferers.
Associated wtih aspirin intolerance, nickel exposure, CF (10-20%), allergic rhinitis, Kartagener's, Asthma (30%)
Imaging: High T2 signal overlaps with appearance of sarcomas, adenoid cystic carcinoma etc.
aka antrachoanal polyp
These arise in the maxillary sinus and protrude into the nasal cavity through the accessory ostium or posteriorly through the posterior choana
They enlarge the maxillary sinus
Common benign sinonasal masses
Usually occurs in the frontal sinus and is an infrequent source of headaches
It can also cause obstructive sinusitis
Is very difficult to see on MR since they are highly calcified
A patient with this plus colonic polyps may have Gardner's sydrome.
Ollier syndrome can also present with osteomas
The inverted papilloma is the most common type (75%)
Associated with swuamous cell carcinoma in 15% of cases
Benigh, but can locally agressively destroy bone, cross the cribriform plate into the skull.
The origin is typically the lateral nasal wall or maxillary sinus.
Imaging: CT - nonspecific inehancing mass in the nasal cavity or sinuses. Look for stippled calcification, but only 20% have this pattern.
MRI - iso to muscle on T1, iso or hypo on T2.
! Most other lesions are homogeneously bright on T2, so iso on T2 is a fairly unique feature!.
Enhancement is variable, 50% are homogeneous, the rest heterogeneous with cenelated/convoluted pattern.
These lesions are resected agressively, but still has 20-40% recurrence rate
Staging of inverted papilloma
I - limited ot nasal cavity
II - Limited to ethmoid and superior maxillary sinus
III - Extends into frontal or sphenoid sinus or extends into inferior maxillary sinus
IV - spread outside the nose and sinuses
T system for maxillary sinus cancer
T1 - limited to mucosa, no bony erosion
T2 - Bony erosion of hard palate or middle meatus, but not posterior wall of the sinus or the pterigoid plate
T3 - Invasion of any of the following: Psterior wall, subcutaneous tissues, floor or medial wall of the orbit, pterygoid fossa or ethmoids.
T4a - Invasions of any of the following: Anterior orbit, skin of cheek, pterygoid plates, sphenoid or frontal sinuses.
T4b - Invasion of: Orbital apex, dura, brain, middle cranial fossa, cranial nerves other than V2, nsopharynx or clivus.
T staging of ethmoid cancer
T1 - restricted to 1 sinus +/- bony erosion
T2 - Invading 2 or more cells in single region or extending to adhacent regiong
T3 - Extends to medial wall or floor of the orbit, maxillary sinus, palata or cribriform plate
T4a - Invasion of : Anterior orbit or skin, anterior cranial fossa, pteerygoid plates, sphenoid or frontal sinuses.
T4b - Invasion of: Orbital apex, dura, brain, middle cranial fosssa, cranial nerves except V2, nasopharynx or clivus.
Sinonasal squamous cell carcinoma
Makes up about 80% of paranasal sinus malignancies
80% occur in the maxillary antrum
75% (or make that 80) of patients are over 50 yrs old
80% have bony destruction at presentation
There are known associations with nickel or c hrome pigment, bantu snudd, cigarettes
Imaging: Usually homogeneously enhacing. Hypointense on T2
Differential includes Lymphoma, invasive papilloma, undifferentiated CA or sarcoma
Enhancement of the dure does not imply neoplasm. almost any inflammatory process with make the dura enhance.
Sign that DO imply malignancy are
Discontinuous enhancement with intervening margination
thickening over 5 mm
Sinonasal mass eroding intracranially
sinonasal undifferentiated carcinoma
Very aggressive with very poor prognosis
Most commonly arises from ethmoid sinus
demonstrates early bone destruction
Often involve adjacent structures, even extending to calvarium
Imaging: Looks lika a squamous cell CA on steroids with areas of necrosis. Enhances heterogeneously
Minor salivary galnd tumors of sinus
Second most common sinonasal tumor after swuamous cell
Most common type is adenoid cystic
Has propenity for perineural spread.
Adenocarcinoma type has predilection for ehtmoid sinuses and occurs with increased frequency in wood workers.
Imaging: variable T2 signal
Nasal septum is the most common site, followed by turbinates.
Associated with melanosis
Propensity for perineural spread. Metastasised easily be hematogenous spread
Presetns as mass high in the nasal cavity or ethmoid vault with calcifications.
Arises from neural crest cells in the nasal vault
Bimodal age distribution 11-20 and middle age (50s)
Often presetns with nasal obstruction, epistazis and decreased olfactory function.
Has a propensity to cross the cribriform.
Can metastasise hematogenously or by lymphatics.
Associated intracranial cysts are pathognomonic.
Excised but has high recurrence rate ~ 50%
Imaging: low T2 signal.
Is very rare.
The most common type is chondrosarcoma followed by rhabdomyosarcoma.
Most common locations are orbit, pharynx, temporal.
Lymphoma of sinonasal region
Most commonly non=Hodgkin type
Occurs mostly in the sinuses
Presents with nasal obstruction (80%), dischanrge (64%), epistaxis (60%)
Can cause septal perforation
75% are T-cell lineage which for some reason likes the nasal cavity and ethmoid sinuses
B-cell lineage likes the maxillary sinuses.
Can be result of PTLD
Mets in the sinonasal region
RCC is most common. It is very vascular and hemorrhages easily.
Other commons sites for RCC include larynx and skin.
Overal RCC is 3rd most common met source in the head/neck region after lung and breast cancers. Overall most common site in head/neck overall is to thyroid
Most common congenital lesion of the nasopharynx.
Arises in the apposition of mucosal surfgace in the midline.
Can get infected on occasion and can be a sourse of persistent halitosis.
Imaging: hypodense on CT. Variable MR signal, usually high T1 and T2.
Nasopharyngeal inflammatory lesions
Adenoidal hypertrophy of HIV
Infected Tornwalt cyst
Mucus retention cyst
Tonsillitis of the adenoids.
Torticolis with rotatory sublucation of C1 on C2 secondary to adjacent inflammatory mass.
Can be caused vby pharyngitis or retropharyngitis.
Spread of JNA
Pterygopalatine fossa (89%)
Infratemporal fossa (85%)
Sphenoid sinus (61%)
Maxillary sinus (43%)
WHO classification of nasopharyngeal CA
I - Squamous cell
II - Nonkeratinizing CA
III - Undifferentiated (SNUC)
II and III are the more common
Consider CA in any case of new serous otitis media in an adult
Most common location is around the fossa of rosenmuller
Bimodal age distribution
12-25 more common in asia and with undifferentiated type.
40-60 more common with westerners, types I and II (Risk for the is EBV)
Nodal spready is first to retropharyngeal and high jugular nodes.
Imaging: CT: isodense to muscle. Infiltration of adjacent tissue is the most reliable sign. Also look for widening of midline soft tissues to more than 1.5-2.0 cm.
MR: isointense of muscle on T1, and Iso or Hypo on T2.
Treatment is non-surgical.
This is the predominant nasopharyngeal tumor in children.
It is very responsibe to chemo
Intracranial extension is common.
Commonly presents with rhinorrhea.
Common location include nasopharynx and palatine tonsils
Imaging: Oval mass iso in T1 and iso to slightly hyper on T2.
Entities associated with macroglossia
Glycogen storage diseases
T staging of oropharyngeal CA
is by size rather then spread
T1 - <2cm longest axis
T2 - greater than 2 and less then 4 cm greatest axis
T3 - over 4 cm
T4a - Invades larynx, or cheek/extrinsic tongue muscles, medial pterygoid, hard palate or mandible
T4b - Invades lateral pterygoid or pterygoid plates, lateral nasopharynx, skull base or encases a carotid artery
Squamous cell CA in oropharync
The most common location is the atnerior of a tonsil and on the tongue base.
Has propensity for invasion into the tongue.
Sq cell CA is also the most common occult primary presenting only with cerivcal lymphadenopathy
Occurs in setting of familial fibrous dysplasia of mandkble, neurofibromatosis, noonan syndrome, Raman syndrome.
Constellation of cherubism, gingival fibromatosis, epilepsy and mental retardation)
constellation of Synovitis, Acne, Pulmoplantalpustulosis, Hyperostosis, Osteitis in association with diffuse sclerosing osteomyelitis of the mandible, inflammation can spread to the skull base and then cochlea resulting in deafness.
is a cystic lesion due to obstruction of sublingual gland duct or manor salivary gland duct in the floor of the mouth.
Simple - above the myohyoid
Plunging - goes through the myohyoid
Imaging : the wall of the cyst usually enhances
Lytic dental benign lesions
Central odontogenic fibroma
Giant cell granulloma
Incisive canal cyst
2nd most common odontogenic tumor.
Most commonly a multiloculated mass
Most commonly located in the mandible (81%)molar region (70%)
Presents with expanded jaw, but painless unless infected.
Often associated with dentigerous cyst
The cortex is eroded or penetrated.
Has a high recurrence rate.
Imaging: On MR, solid cystic with mural nodules and peripheral enhancement.
Brown tumor of mandible
Lytic erosion of lamina dura,
porrly defined mass.
Central odontogenic fibroma of mandible
Multilocular lesionwith sclerotic borders and expanded mandible
Lytic, lucent lesion adjacent to an unreupted tooth, which spares the cortex. The margins are sclerotic.
Most commonly at an unrerupted 3rd molar or canine. This lesion is asymptomatiC
Giant cell granuloma of the mandible
Well differentiated multilocular lucent lesion with sclerotic margin
Occurs in children and young adults
Incisive canal cyst
Lucent lesion in the midline of the hard palate with hyperostotic borders at the canal
Globulomaxillary cyst of mandible
Lucent lesion between the lateral incisor and canine in the maxilla
Unilocular or multilocular expansiale lucent lesion, which erodes the cortex, but does not perforate.
Usually located in posterior mandible and has thin walls (see above)
Associated with basal cleft nevus syndrome
Lytic lucent lesion at the paex of an erupted, nonviable tooth.
There is loss of the lamina dura and hyperostotic borders.
Sclerotic dental lesions
Adenomatoid odontogenic tumor
Garre's sclerosing ostemylitis
Circular radiodensity arrached to mandibular tooth with very thin border with spicules and surrounded by lucency. The mandible is expanded and the tooth is viable
Usual age is up to 20s
Garre's sclerosing osteomyelitis
A sclerosing bony lesion, which is hot on bone scan. There is periosteal reaction and apical lucency.
The adjacent teeth are carious and nonvital, usually mandibular region.
Miniature tooth looking lesion in the maxilla (consists of enamel) with peripheral lucent zone.
Also can be irregular, complex opaque mass in mandible molar region
Patient is usually young with mass between canine and premolar
Lytic lesion with multiple small calcifications
Associated with impacted teeth
Usually mandibular molar region
Congenital lesions of the pyriform sinus
This sinus is often the drain site for 3rd cleft cysts.
The apex of the sinus may drain 4th cleft cyst (but still very rare)
Seen near the cricopharyngeus posteriorly.
Rate increase with age, as does the size
Develops at the natural Killian's dehiscence between the cricopharyngeus and inferior pharyngeal constrictor.
If very large the diverticulum may veer to the side and no longer be purely posterior midline.
This is a lateral diverticulum
On averal small than Zenker's and occurs at any age.
Congenital lesions of the larynx
occur at the level of true cords
Laryngeal submucosal cyst
Most common benign mass in the larynx.
Due to obstruction of a minor salivary gland.
Common location is in suproglottis
Can cause airway obstruction (rarely)
Differential includes thyroglossal duct cyst
Characteristics are the same as elsewhere.
Benign, but associated with squamous cell carcinoma
Benign lesion occuring mostly in 1-2 year olds
50% are also associated with cutaneous hemangioma
Responds readily to steroid therapy, or regresses with age just like the cutaneous type
Imaging: CR - asymmetric narrowing of the airway
CT/MR - smooth, asymmetric, enhancing mass in the subglottis which may compromist the airway.
61% occur in the larynx
23% in tongue/oropharynx
only 9% in trachea.
Imaging: very low T1 and T2 without enhancement
Neurogenic tumors of the larynx
Schwannoma or neurofibroma
Eriepiglotic folds are most common location
Imaging: exophytic or submucosal enhancing mass
Rare complication after a standard therapeutic radiation dose to the larynx.
Presents with soft tissue swelling and loughing of the arytenoid cartilage.
There is subluxation, fragmentation, sclerosis and collapse of the thyroid cartilage.
May or may not be gas bubbles around the cartilage
Chondroid tumors of the larynx
Cartilage structures may develop chondromas or chondrosarcomas. 70% occur in the cricoid.
Look for the popcorn and arcs rings calcification
Usual age is 40-60 with significant male predominance 5:1
Spindle cell sarcoma of the larynx
Has characteristics of both squamous cell and sarcoma on histology
Larynx is the most common location
Similar prognosis to squamous cell.
Skull base causes of vocal cord paralysis
Mets to jugular foramen
These lesions also often involve cranial nerves IX through XII
High vagus lesions
Cuase swallowing and gag reflex dysfunction, pharyngeal muscle atrophy, deviated uvula
Vocal cord paralysis signs
There is cord atrophy
Dilation of the laryngeal ventricle
Meial orientation of the affected cord
Dilation of the ipsilateral pyriform sinus and valecula
Medial orientation of the aryepiglottic fold
Anteromedial deviation of the arytenoid cartilage
Posterior cricoarytenoid muscle atrophy
Lymph node slevels
Ia - submental
Ib - submandibular
II - cervical above the hyoid
III - cervical below hyoid to level of cricoid cartilage
IV - cerivcal chain below the cricoid.
V - posterior triangle
VI anterior to thyroid in the anterior jugular and visceral chains
VII - superior mediastinum
The surgical separation of II and III is the bifurcation of the carotids
Congenital lymphatic lesions of head neck
In dexreasin order of size
Most are apparent at birth
Most common location is the neck (70%) followed by axilla (20%)
Can be diagnose in utero when large enough to be a cause of polyhydramnios.
Can spontaneously hemorhage.
The lesion is compressible and distorted by arteries.
Imaging: CT - Hypodense, multiloculated
MR - vaiable depending on protein content and hemorhagic products
Associated with Turner syndrome, Noon syndrome and fetal alcohol syndrome.
A classic causes of inflammatory cervical adenitis in children. aka Scrofula
Presents as a painless posterior neck mass with or without systemic symptoms.
In the US usually caused by TB, worldwide usually from contaminated milk with M Bovis
Uncommon to have concurrent pulmonary TB
There are usually bilateral necrotic nodes, usually level V. Often ringlike enhancement. The interveening fat planes are obscured. Overall appearance like a multiloculated mass.
Differential includes TB and other granulomatous diseases, thorotrast, treated lymphoma, anthracosilicosis, thyroid carcinoma nodal mets, adenocarcinoma, squamous cell carcinoma.
Nodal distribution is 70% chest, 10% head and neck.
Patient usually <30 years old, asymptomatic.
Imaging: the nodes are avidly enhancing (unique appearance) with stellatecentral non-enhancement
Presents with multiple enlarge non-necrotic nodes.
The Waldeyer ring is hypertrophied (also happends in AIDS)
Differential includes AIDS and Sarcoid.
Look at the parotids, if there are mutiple intraparotid cysts, favors AIDS, if it is diffusely infiltrates, favors Sarcoid
Cat scratch disease
Another cause of bilateral enlarged nodes, often with edema around the nodes
Perinaud oculoglandular syndrome
Constellation of conjunctivitis, polypoid granuloma of palpebral conjunctiva and periauricular, parotid and periparotid lymphadenopathy.
Cause by Bartonella, same as cat scrathc disease
Histiocytic necrotizing lymphadenitis
Patient usuall young and asian descent
There is adenopathy, fever and leukopenia.
Adenoapthy is large, variable (with or without necrosis, with or without enhancement)
Looks very much like lymphoma on CT
Chronic inflammation with diffuse hypervascluarl adenopathy in the cervical chain, predominantly level I.
There is eosinophilia.
The salivary glands can also be swolen and tender.
Patient usually asian descent male ranging 10-30 years.
Imaging: US - hilarl hypervasclularity on doppler.
Causes of calcified lymph nodes
Non-TB gramulomatous infection
Mucinous adenocarcinoma mets
Burnt out inflammation (a rarity)
Nodal staging of squamous cell CA
N0 - negative
N1 - <3cm diameter
N2a - Mets to a single ipsilateral node which is greater than 3, but less than 6 cm diameter
N2b - Multiple nodes, none greater than 6 cm diam
N2c - multiple bilateral or contralateral nodes, again none over 6 cm diam
N3 - any node over 6 cm diameter
Lymphadenopathy from Thyroid CA
In 50% of patients this is a first presenting symptom
Mets can be cystic, calcified, vascular, highly enhancing or colloid containing.
Can be tiny or T1 bright or retropharyngeal or hemorrhagic. Basically any appearance at all.
Adenopathy due to Lymphoma
Most common non-inflammatory cause of unilateral neck mass among 20-40yr olds
Usually non-Hdgkin type in the head/neck region. But this is actually the 2nd most common region for NHL after the GI tract.
Often ivolves Waldeyer ring.
With a history of Mononucleosis, Hodgkin type is more common.
Hodgkin type seems to progress orderly from one chain to the next.
Non-Hodgkin type leaps around haphazzardly
Ducts of Rivinus
Drain sublingual salivary glands
Duct of Bartholin
A dominant sublingual duct that opens to the Wharton's duct.
Cystic masses of the parotid gland
Branchial cleft cyst
1st branchial cleft cyst
Located in the parotid gland or around the EAC
Two classification systems
type 1 - parotic
Type 2 - Anteriro neck drain through parotid to EAC
I - anterior/inferior to pinna, communicates to EAC
II - at the angle of mandible
2nd branchial cleft cyst
Makes up the majority of BCCs, ~90%
Usually located anterior to mid sternocleidomastodi deep to the ICA at angle of mandible
Drains to parapharyngeal basilar fossa or skin
3rd branchial cleft cyst
Opens to about the location on the skin or to the pyriform sinus.
Autoimmune chronic sialadenitis
Presents with truncated main ducts with punctate.globuloar collections peripherally in the gland parenchyma
Painless enlargement of salivary glands, usually parotid.
Associated with DM, EtOH, hypothyroidism, meds(phenothiazine, diuretics), obesity, starvation
Imaging: CT - density of the gland slightly increased. T2 also slightly hyperintense but not as bright as an inflamed gland
Inflammation of the salivary gland.
Usually associated wi th sialectoasis (dilated ducts)
An obstructing calculus is the usual cause.
Microabscesses may be seen with pain and fever
Causes of salivary gland inflammation
Overall Mumps (esp parotid)
Uncommon, but Strep, Haemophilus, Staph
Causes of acute parotitis
Grannulomatous disease (TB, Candida, Catscratch)
Idiopathic (postpartum for some reason)
Inflammation of the mainsalivary duct system
Mikulicz(Limited to salivery glands without other findings. Equivalent to Sjogren type 1)
Associated 10x elevated risk of lymphoma-which often starts in parotid glands and is predominantly Non-Hodgkin type
Imaging: MR punctate, globular, cavitary, destructive appearance of ducts associated with lymphoepithelial cysts and nodules.
Differential: lymphoepithelial lesions of HIV
A mucus plug in the duct leads to a painful swolen gland.
makes up over 80% of benigh parotid gland neoplasms. (The rest are monomorphic type and myoepitheliomas)
rule of 80
80% in superficial lobe
80% remain benign
(only about 0.5% is multicentric)
Patient is usually a middle age woman.
The lesions is well defined, solid and round
Imaging: density similiar to muscle on CT with midl-moderate enhancement.
On Mr, lesion is T2 birhgt, T1 dark with a complete capsule dart on all sequences. The contour is lobulated with or without cystic degeneration and calculi.
Include myoepithelioma, oncocytic adenoma, canalicular adenoma
They loosk similar to pleomorphic, but more common in sumadibular gland (as opposed to pleomorphic, more common in parotid)
aka cystadenoma lymphmotosum.
Can be cystic or lymphoma like (hence the name)
Nearly exclusive to the parotid.
Most common multible bilateral tumors of parotid.
Patient is usually an elderly male
May have a tumoral cyst, which favors the parotid tail
There is no malignant potential
Imaging: low T1 signal, heterogeneous on T2.
Increased uptake on pertechnetate scan
Rare, benign, exclusive to the parotid gland
MR characteristic similar to pleomorphic adenoma
Hot on scintigraphy
Most common salivary gland tumor in children
Associated with cutaneous hemangiomas
Makes up 90% of parotid gland tumors in neonates
Like cutaneous hemangiomas, tends to spontaneously involute.
Imaging: Highly enhancing, High T2 signal
Second most common benign parotid gland tumor ub chukdren
(3rd is pleomorphic)
Multiple parotid gland masses diff
Acinic cell carcinoma
Lymphoepithelial lesion of HIV
Most common malignant lesion in parotid gland
(in other salivary glands it is adenoid cystic carcinoma)
30% of salivary gland malignancy overall, of which 60% are in parotid.
Also Most common pediatric salivary gland malignancy
No specific imaging characteristics
Adenoid cystic carcinoma
Most common malignancy in submandibular, sublingual and minor salivary glands.
Notorious for perineural spread (in ~50-60%)
Frequently recurrs post resection
Rlentless but slow growth. Survival measured in decades
Imaging: T2 variable signal with low T1
On CT isodense to muscle. Mild to moderate enhancement
Acinic cell carcinoma
Most common primary meltifocal malignancy of parotid gland
Exclusive to parotid gland
3% are bilateral.
No specific imaging characteristics
Cancers arising from pleomorphic adenoma
10-25% of pleomorhic adenomas degenerate, usually to adenocarcinoma
Progress may be rapid with distant mets
Masticaor space congenital lesions
Branchial cleft cysts
Occurs due to gnashing of teeth
Bilateral enlarge mastication muscles.
Either idiopathic or due to malocclusion, or excessive chewing.
Constellation of precocious puberty, Cafe-au-lait spots, polyostotic fibrous dysplasia.
It can affect the mandible unilaterally.
Usually see in young women.
Bilateral bone lesions of mandible with bubbly appearance and groundglass appearance
Fibrous dysplasia involving the skull
10-25% of monostotic cases do this
as well as 50% of polyostotic cases
Most frequently involved skull bones are mandible, maxilla, calvarium
Beckwith wiedeman disease
Constellation of craniofacial dysmorphysm, macroglossia, omphalocele, gigantism, visceromegaly and abdominal neoplasms
Chronic facial/jaw pain
9:1 women to men.
Often precipitated by traumatic event
Meniscus, which isusually centered over condylar head at 11-12 o'clock
Lateral pterygoid opens the jaw and inserts on the anterior portion of the meniscus.
Anterior meniscus dislocation is most common (position is at 9-10 o'clock). May reduce on opening with a click
Medial or lateral component to the dislocation is possible, but rare and even more rarely isolated.
Infiltrative lesions of masticator muscles
Beckwith Weidemann disease
Glycogen storage diseases
Benign parapharyngeal space tumors
Very uncommon, there a few tissue types here.
Lymph nodes can have inflamation or mets
Rarely minor salivary glands can occur and can have any salivary gland tumors
Thyroglossal duct cyst
Most common non-odontogenic cyst in the head/neck. About 70% of neck masses overall
3/4 are midline
1% cancer risk
Riedel thyroidits and radioation thyroiditis
Both lead to fibrosis
Both hyperdense on CT
Both have low signal on MRI.
Enhancement is variable
Riedel is associated with retroperitoneal fibrosis and sclerosing cholangitis.
Riedel is also distinguished by encroachment in the adjacent tissues
Most common benign tumor int he thyroid
70% are solitary
Inhomogeneous density, but well circumscribed
Can have calcifications, but this is not a distinguishing feature
Can be autonomous, in which case they suppress the remaining thyroid
Malignant thyroid cancers
Make up only 4-6% of biopsied nodules
Mor common in men, and as a solitary nodule
Papillary follicular and mixed types make up approximately 80% overall.
Medullary accounts for 10%
Undifferentiated or anaplastic 3%
All can be well circumscribed or poorly defined without any specific CT or MR characteristics
All can be cystic, calcified, hemorrhagic, proteinaceous. Only way to tell is biopsy
Papillary cancer of thyroid
Most common of the thyroid malignancies making up over 50%. In pediatric cases less than 4 yrs old it is 5x as common as everything else combined. Also women more than men
Cervical nodes are the most common presentation, often the only presenting symptom
Lymphangitic spread is the rule (compare to follicular, which spread hematogenously)
Very variable appearance.
Nodal mets can be highly vascular.
Look for tracheal involvement.
when >180 degreees incased, invasion is implied
also look for intraluminal mass or
displacement >2.5 cm
Look for esophageal invasion
Abnormal signal/enhancement of the wall
>270 degrees encase invasion is implied or
The prognosis is much worse than papillary
The rule is hematogenous mets spread (vs papillary which is mostly lymphangitic)
Imaging is just as non-specific
Rare, making up 7-10% overall
10% are associated with MEN II and some are familial
The tumor is active, secreting calcitonin and can be setected on serum tests
Look for stippled calcifications in the mass
Highly agressive, large and bulky on presentation
Population is older on average compared to papillary cancer.
Can be thallium or gallium avis, but not iodine.
Usually already invasice in trachea and esophagus on presentation.
Look for endokuminal mass and/or >180 degree encasement of the trachea
Non-hodgkin lymphoma of thyroid
Usually seen as a solitary nodule. Multicentric in only ~13% and diffuse in 7%. Bilateral 50%
Occurs more in women, elderly population.
Hashimoto thyroiditis increases risk
Hypoechoic on US and hypodense to thyroid on CT
Metastasis to the thyroid
Lung cancers brain cancers and RCC
aka Werner syndrome
autosomal dominant on chromosome 11
90% has hyperparathyroid, but only 2% hyperplastic
Thyroid goiters, adenomas are rare
Pancreatic adenomas, Insulinomas, gastrinomas (30-80%) causing zollinger-elison syndrome, adrenal cortical adenomas (30-40%)
Rarities also include glucagonomas, vipomas, carcinoids.
aka Sipples's syndrome
Autosomal dominant on chromosome 10
Parathyroid hyperplasia (20-50%)
100% medullary thyroid carcinoma
NO pituitary lesions
>50% have bilateral pheochromocytoma
Also can see scoliosis
aka mucosal neuroma syndrome
Autosomal dominant on chromosome 10
Almost no parathyroid lesions with this one
100% medullary thyroid cancer
No pituitary lesions
50% have bilateral pheochromocytoma
Unlike type II, this one has other lesions: Mucocutaneous neuromas in 100%, marfanoid facies, cafe-au-lait spots, intestinal ganglioneuromatosis in 100%.
Most commonly found in anterior mediastinum
The appropritate study is MIBI scan using 10-25 mCi to look for the ectopic tissue. Use concurrent Tc pertechnetate to subtract the thyroid tissues. Also can do MRI.
On MRI,ectopic parathyroid adenomase are T2 hyperintense. Atypical T1 or T2 hyperintensity corresponds to degeneration. There is avid enhancement.
Neck cystic masses
Branchial cleft cysts
Thryglossic duc cyst
Thyroid and thymic cysts
Branchial arch I
Origin of V3
Mandible, Malleus, Incus, Tensor rympani, Masticator, Anterior digastric, Meddle ear, Tonsils
Treacher collins syndrome, abnormalitis of the external ear, hypoplastic mandible
Branchial arch 2
Precursor of CN VII
Precursor of menubrium of malleus, long process of incus, posterior digastric, inferior facial canal, tonsils, parathyroid
Persistent stapedial artery
Branchial arch 3
Precursor of CN IX
Precursor of Hyoid, stylopharyngeus, parathyroids, thymus, pyriform sinus
Diseases: DiGeorge syndrome, absent thymus and 3rd parathyroid gland
Branchial arch 4
Precursor of left aorta and right proximal subclavian
Precursor Thyroid cartilage, cuneiform, inferior pharyngela constrictor
Diseases: Aberant right subclavian
Branchial arch 5
Precursor of pulmonary arteries. CN X recurrent laryngeal branch
Precursor of the cricoid, arytenoids, trachea and intrinsic muscles
Spinal cord blood supply
Cervical: there is 1 anterior and 2 posterior spinal arteries, all formed from the vertebral arteries
The anterior supplied the anterior 2/3 of the cord including most gray, corticospinal and spinothoalamic tracts
Midthoracic: Supplied from intercostal branches lumbar arteries and supreme intercostal branches
Lower thoracolumbar to filum: supplied by artery of adamkiewicz, origin commonly on the left from T9-T12 levels. Enters with the nerve roots and makes the characteristic hairpin turn
Artery of Lazordes - uncommon, formed from internal iliacs. Supplies the conus medullaris
Calcifications in intervertebral disks
Foraminal disk herniation resulting in nerve compression with severe pain
Degenerative disease in children with vertebral wedging resulting in lower thoracic kyphosis.
Onset usually in puberty.
Look for wedging over 5 degrees each in 3 contiguous vertebrae
Schmorl's nodes are common.
End-plate osteophytes with significant degenerative disease in the spine.
Associated with anterolateral disk protrusion
Associated with DJD
Characteristic location is adjacent to a facet joint
Looks like a rounded poterolateral extradural mass and may be posterior paraspinal
Most are synovial cysts, some are ganglion cysts
Most common levels are lumbar L4-5 the L5-S1
The wall of the cyst can calcify and there may be gas in the cyst from vacuum phenomenon
Associated with spondylolisthesis
Ossification of the posterior longitudinal ligament
Is an inflammatory degenerative condition
Associated with degenerative disease of cervical spine
Same rate in men and women, typical age 40s to 60s
Can result in compression of cervical cord with myelopathic symptoms
Differential includes calcified heniated disk, osteophytes, calcified meningioma.
! OPLL is the only thing on this differential that has marrow inside!
AKA Forestier disease
Ossification along the anterior and lateral aspect of the spine with hyperostosis of ligmant insertion and ligmant ossification in axial and appendicular skeleton.
There is osseous bridging of at least 4 contiguous vertebral bodies.
Most bone is at the intervertebral disks
Hypertrophy of transverse processes.
Disk space is actually preserved.
Facets usually not involved.
Differential includes ankylosing spondylitis, but this involves facet joints and SI joints, which DISH does not.
Inflammatory disease involving the SI joints and spint enthesopathy
Incidence about 1.4% in young men. Association with HLA B27.
Key word is Bamboo spine.
Erosion of the endplates and enthesopathy results in squaring of vertebral bodies.
Another buzz word is "shiny corner" on the plaing films.
Makes the spine prone to fractures, progressive spinal deformity, atlanto occipital or atlantoaxial or rotatory subluxation.
Imaging: MR has T1 hypo and T2 hyperintensity in vertebral bodies with enhancement.
Interpedicular <16 mm at L4-5, >20 mm at L5-S1
Canal should be 1.45 square cm.
Ligamentum flavum normally 2-4 mm thick, >5 is hypertrophied
Lateral recess should be >2mm, <2 is stenotic - hypertrophy of the the suprior articular facet is the most common cause.
Lumbar cana diameter should be >10 mm. <10 mm is stenotic.
Decreased T2 signal, Decreased T1 in adjacent bone amrrow
There is obliteration of the intranuclear cleft
The disk and adjacent andplates enhance, which can be seen even in asymptomatic patients
Enlargement of dural sac and root slevves along the spinal column, most often int he lubar/sacral region.
Resultsin scalloping of the posterior vertebral bodies, spinal canal dilation, widening of interpedicular distance and neral foramina.
There is thinning of the cortex.
Association with anterior and posterior meningoveles
Common in Marfan's, Neurofibromatosis, Ehler's-Danlos, ankylosing spondylitis
Causes of failed back syndrome
Central stenosis, foraminal stenosis
Early postop complications
Insufficient nerve decompression
Recurrent or residual herniation
Wrong level surgerized
Inflammation of spinal leptomeninges, particularly of the roots, resulting in adhesions
Associated with myelography, surgery, pantopaque use (not in use anymore though newere caontrast agents are safer), also infection (TB and pyogenic), subarachnoid hemorrhage other inflammatory diseases.
In worse cases there is worsening morphology of the thecal sac, adhesion of the nerve roots and clumping resulting in "pseudofilum"
Occurs in 16% of failed back cases.
May or may not enhance.
When due to TB, also involves the spinal cord and meninges with loss of cord margins with meningeal enhancement and enhancing nodules
Causes of diffuse roo thickening
CHronic inflammatory demyslinating polyradiculopathy
Hypertrophic interstitial polyneuritis
When acute onset, pain is always present
Not always so in chronic cases
Most common cuases are Staph then Strep, peprostreptococcus, E. coli and proteus
Most common location is lumbar
MRI is most specific
Best sequence is T2 fat sat or STIR. Correlated to enhancement. Gallium lableled WBC label this very well, but there is strong background from any inflammation.
Occurs in dialysis patients
Usually cervical spine affected frist. Aggressive appearance similar to infection with distruction of disk space and adjacent vertebral bodies.
!T2 signal is low here (infection is high) and there are no clinical signs of infection!
Granulomatoses of the spine
Most common is brucellosis followed byt TB, fungal (blaso, crypto, coccidio).
Brucellosis is lower lumbar-tropic and less destructive than TB.
TB is likes the lower thoracic region (Pott's disease), is indolent, also causes epidural disease (paravertebral and subligamentous). There is disk sparing and vertebral body destruction late in the disease.
Key word is gibbus deformity.
Spreads along the anterior longitudinal ligament to multiple levels
50% have concurrent pulmonary disease
Occurs from direct extension or hemorrhagic spread
Most common bug is Staph aureus, also gm negative rods, anaerobics, mycobacteria, fungi
Associated with blunt spinal trauma with hematoma
Most common location is dorsal epidural space.
On MR T1 signal is decreased as compared to the cord, and T2 is increased
Enhancement is variable homogeneous, peripheral or mixed
Differential includes subdural empyema.
Spinal cord sarcoid
the spinal cord is involved in 6-8% of neurosarcoid cases
Most common level is cervical
There are nodules on the surface of the cord and possiblyi on nerve roots (similar appearance to tumor nodules).
There may be cord enlargement.
If intramedullary, can be diffuse or mass-like
MR demonstrate T2 hyperintensity with diffuse or nodular leptomeningeal enhancement.
Causes of pachymeningitis
Intramedullary lesions in AIDS
Subacute necrotising myelopathy
Defined as demyelination and perivascular lymphocytic infiltrate and necrosis at multiple spinal cord level, often entire cord cross-section .
Has T2 hyperintensity and variable enhancement.
Connective tissue diseases
Autoimmune (Lupus, RA, Sjogren)
Vacuolation in the spinal cord white matter. There are lipid laden macrophages involving dorsal columns and lateral corticospinal tracts.
Also can occur anywhere else.
Spinal cord MS
Lesions are T1 iso or low, and bright on T2
60% are cevical
Typically does not involve the entire cross-section, but does cross the gray-white boundary
Usually spans less than 2 segments
The cord is usually normal size, only about 10% of lesions expand the cord
Enhancement is often seen in the acute phase of symptoms
Spinal cord lupus
Lesions are T2 hyperintense and the cord is often expanded.
Usually spans more segments than MS, about 4-5 (as compared to 2)
about 50% of lesions enhance
Suabcute combined degeneration
Due to B12 deficiency
Involves the cervical and upper thoracic cord as well as optic tracts, brain and peripheral nerves
Most frequent cause in the US is pernicious anemia.
There is demyelination and axonal loss in posterior and lateral spinal cord columns
Causes of degeneration in posterior spinal cord columns
B12 deficiency SCD
Toxins (organophosphates, thallium, vincristine)
Effects of radiation on spinal column
Conversion to fatty marrow with associated increase of T1 signal and decrease of T2 signal.
The cord can T2 hyperintense secondary to radiation myelitis or residual tumor. Cord atrophy may also be seen.
Adult tethered cord
Symptoms usually precipitated by event such as trauma
Women more often than men. Pregnancy, pelvic exam and child birth are often the enciting event
Symptoms include back pain, led weakness and incontinence
The conus is below L2 and filum is >2 mm thick
Causes of low T1 signal in vertebral bodies
Replacement of fatty marrow
Modic I and II changes
anemia (resulting in red marrow conversion)
Blood transfusions (deposition of iron?)
Chronic renal failure
Causes of increased T1 signal in vertebral bodies
Increased fatty marrow
Modic II changes
Lesions causing hydromyelia
The spinal canal extends from the obex of the 4th ventricle to the filum
There are normal expansions in the conus called the terminal ventricle (sometimes the 5th ventricle), which obliterates by age 40
There are 3 types of syringomyelia
Central canal syrinx communicates with the 4th ventricle. This type is associated with hydrocephalus
Second type occurs in the central canal and does not communicated with the 4th ventricle. It is associated with Chiari I, extramedullary intradural tumors, arachnoid cysts, cervical region spinal stenosis and basilar invagination
Third type is centered in the spinal cord parenchyma, not the central canal, usually in watershed regions and associated with direct spinal cord injury.
There is also eccentric syrinx, which is very off center in the cord and can be confused with arachnoid cyst.
Finally there is such a thing as exosyrinx, which is evaginated from the cord.
Causes of syringomyelia
Spinal cord tumor (ependymoma, astrocytoma, hemangioblastoma)
Vertebral body tumors
Causes of enlarged spinal cord
Demyelinating (ADEM, MS, other, transverse myelitis
Infectious (swelling from meningitis, AIDS)
Inflammatory (Sarcoid, SLE)
Vascular (acute infarct, AVM, Cavernous angioma, Hemorrhage)
Venous hypertension (aka Foiix Alajouanine)
Cysts associated with tumor of spinal cord
Rostral or caudal to the tumor are secondary to dilation of central canal. This does not enhance, not echogenic, no septation, and resolve when tumore is resected.
Cyst occuring within the tumor is a tumoral cyst. This is common with astrocytoma. It enhances peripherally
Astrocytoma of the cord
make up 40% of spinal cord tumors overall
Typically seen in children, it is the most common intramedulary tumor in that age group.
In adults the age range is 20s to 40s, mean 29, M>F
Level is Thoracic>Cervical>Lumbar
Tumor is hypercellular, large, takes up full diameter of the cord, has no obvious margin and is offen eccentric in the cord.
On imaging there may be mild scoliosis and increased intrapedicular distance, vertebral scaloping. High T2 signal, low T1 signal. Average length is 7 segments. Often a c ystic component. Enhancing.
Clinical presentation is with pain, parasthesias and motor signs.
In children the lesion is WHO Gr 1 with good prognosis.
When associated with neurofibromatosis is infiltrative and not resectable.
Ependymoma of the spinal cord
Focal-ish tumor spanning an average of 3.6 segments, but can be very expansive
Usually central in cord
50-60% occur in age range 20s to 40s, this is the most common intramedularry tumor in adults
The mass is unencapsulated, but well circumscribed, noninfiltrating, slow growing
Histologically benign. Often resectable
Level is 44% cervical, 23% upper thoracic
Mets usually to retroperitoneal nodes
Ependymoma outside the CNS can occur in the broad ligamtns and sacrococcygeal.
Can cause SAH
Can have extensive cysts.
Most common primary tumor in the lower cord conus and filum terminale
On imaging isointense on T1, hyper on T2. Multinodular with surrounding edema
Likely to hemorrhage, h ypointense rim (cap sign) with hemosiderin. Commonly enhances.
Makes up 13% of the cord ependymomas overall
Arising in filum with extension into the conus
Mean age is 35, m>f
Presents with low back pain, lower extremity weakness, incontinence
Multilocular, encapsulated, mucing containg, often hemorhages and has calcifications
Mr T1 isointense, T2 hyperintense and enhancing
Hemangioblastoma of the cord
Vascular lesion susually in cervical and thoracic coed. 3rd most common intramedullary spinal cord tumor overall
Causes diffuse widening of the spinal cord
Has solid and cystic components, The solid component enhances.
Can be seen on angio. Has arterial feeders and a draining vein
Variable T1 and T2 signal
1/3 is associated with von hippel-landau, in which case often mutiple. Otherwise usually solitary.
Ganglioma of spinal cord
A rare tumor. Most frequently seen in children and young adults, meadian 12
Histologically has large neoplastic neurons or ganglion cells with glial cells. Grows slowly, considered benign
Most are in the cervical region, but can infiltrate the entire cord, usually extending 8 segments or more.
Can cause scoliosis and bony remodeling
Mixed T1 and T2 signal characteristics. There are tumoral cysts, parchy enhancement extends to the pial surface.
There ino edema, no hemosiderin, no calcs.
Treated by resection
Symptoms are nonspecific (headache, back pain and/or focal neural)
Usually spreads by ingrowth via circhow robin spaces.
Cervical region most commonly involved.
Usually solitary, Usually extends 2-3 segments
Low T1 signal, high T2 signal with prominent edema and avid homogeneous enhancement.
Lesions that metastasize to the sp cord or meninges in children
Choroid plexus tumor
Lesions that metastasise to spincal cord or menings in adults
Lung, breast, renal gastric tumors
Meningioma of the spine
25 % of spinal tumors overall, usually thoracic
May coexist with neurofibromas in NF2 and may calcify
Amost all are extramedullary intradural, some are extradural
T1 isointense and T2 hyperenhancing.
Exerts mass effect causing CSF collection aboe and below.
aka HMSN1 (hereditary motor and sensory neuropathy), autosomal dominant
Slowly progressive distal atrophy (commonly peronela distribution) with pes cavus and scoliosis.
Posterior columns, optic and acoustic nerves are often involved
HMSN III autosomal recessive
Slow progressive motor and seonsory loss and ataxia
Scoliosis and pes cavus seen frequently
Enlarged peripheral and cranial nerves with hypmyelination. There is variable enhancement
Chronic inflammatory demylinating polyradiculopathy
An acquired process
Slow onset of proximal weakness, paresthesias, numbness
Cranial and peripheral nerves are enlarged with or without enhancement
Often with lesions in the brain similar to MS
Enlarged peripheral nerves
Chronic inflammatory demyelinating polyradiculopathy
Usually seen in young patient, first 3 decades or so
Most are at thoracic level
In lumbar spine associated with myelodysplasia or tethered cord
Can compress the cord or cauda equina
Gross fat signal in the spine
Pantopaque (not used anymore)
Lesions commonly metastasizing to the spine
Brain tumors, prostate, lung, kidney
Ewing sarcoma (likes sacrum and lumbar)
Neuroblastoma, melanoma, lymphoma, leukemia, multiple myeloma, sarcoma
Pelvic lesions metastasize through Batson's epidural venous plexus.
Prostate, breast, caricnoid, ovarian transitional cell carcinoma, lymphoma are blastic with decreased T2 and T1.
Breast mets have 2 types
estrogen and progesterone positive tend to be osseous, not to brain
Estrogen negatice ones tend to go to brain, not to bones
CT features of benign spinal fractures
Puzzle sign, all fragments are present and fit together
There is retropulsion of fragments into the spinal canal
Fracture lines in cancellous bone of the vertebral body
Thinintravertebral vacuum fenomenon
Ct malignant fracture features
Destruction of anterolateral or posteirior cortex of vertebral bodies
Destruction of cancelous bone
Destruction of pedicle
Focal paraspinal soft tissue mass
Neural creast origin tumors
Accur in infancy.
Arise from sympathetic plexus
<5 years, neuroblastoma
5-8 years Ganglioneuroma
Cacification seen in 30% and sometimes hemorrhage
Location is usually paravertebrla, usually at thoracic level
The tumor extends through goramin to compress the neural sac
Osteobrlasoma vs osteoid osteoma
The differential factor is size. The lesion over 1.5 cm diameter is an osteoblastoma. If less than 1.5 cm its an osteois osteoma
Both have a propensity for the posteior elemets of the spine and transverse processes
There is a lytic or calcific nidus with a sclerotic rim and characteristc night time pain relieved by aspirin
Patients are mostly children
Then involving the spine, its usually in a vertebral body
The lesion is rapid growing causing bone destruction and vertebral collapse leading to vertebra plana
Differential includes Hurler syndrome or Morquio type mucopolysaccharodoses. Both produce bullet shaped vertebra
Causes of vertebra plana
Eosynophilic granuloma (children)
Fracture (osteogenesis imprefecta)
Tumors (leukemia, myeloma)
Spinal dural arteriovenous fistula
aka Foix-Alajouanine syndrome aka Type I
Is the most common spinal vascular malformation
The nidus is in a nerve root sleeve, usually dorsal aspect of the lower thoracolumbar region
Patient usually 40s to 50s and mostly male.
There is insidioius onset of symptoms
Hemorrhage is rare
85% are fed from a single radicular artery, draining to pial veins, leading to venous hypertention, dilation, stasis edema and ishcemia, which may result in spinal crod infarction.
The feeder level is usually different from the anterior spinal artery.
Best diagnostic procedure is angiography. on MRI lood for flow voids.
Lesion increased intramedullary signal on MR and peripherally decreased T2.
Associated with subacute necrotizing myelopathy
Types 1 and 4 cause venous engorgement and can not be destinguished by MRI or CT-angio required.
Types 2, 3 and 4 are congenital and associated with syndromes like Cobb and Osler-Weber-Rendu
Type 1 is acquired.
Type 2 is intramedulary with a nidus.
Type 3 are intrameduallry with extramedullary and extraspinal extension: more common under age 30.
Type 4 arises directly from anterior spinal artery.
Spinal cord AV malformation
Feeder branches are at the level of anterior or posterior spinal arteries. Flow is feeder to nucleus to spinal veins
Associated wtih spinal artery aneurysm.
Symptoms are acute from hemorrhage, including progressive myelopahty.
This malformation is less common than SDAF
Spinal cord AV fistula
Lesion is intraduaral extramedullary and there are no inrvenin cappilaries
The vessels are on the pial surface
Lesions can be ventral or lateral and can invovle the anterior or posterior spinal arteries.
Symptoms can be progressive or acute in onset (from hemorrhage)
Associated with venous aneurysm
Causes of subacute necrotising myelopathy
Spontaneous dural AVM
Vacuolar myelopathy of AIDS
Venous HTN (Foix-Alajouanine)
Causes of spinal subarachnoid hemorrhage/hemtomyerlia
Spinal cor tmor
Coarctation of the aorta
Spinal arterial anerysm
Apinal venous aneurysm
Cervical nerve root avulsion
The rrods are absent on the affected side
The cord is displaced tot he contralateral side
A pseudomeningocele may form, and may not commynicate with the subarachnoid space-acting like an extramedullary mass
Stable spinal fracture types
Subluxation is anterior if present
Burst fracture of lower cervical region
Fracture of posterior neural arch
Unilateral facet dislocation
Spinous process fracture (clay shoveler's)
transverse process fractures
Compression fracture with <25% heigh loss
Type I odontoid fracture
End plate fracture
Bilateral C1-2 dislocation
Bilateral facet, laminar or pedicle fractures
Type II odontoid fracture
Occurs from hyperextension
Results in fracture dislocation of Ce
Bothe pedicales are fracture with anterior subluxation of C2 body on C3 without movement of the posterior ring
An ossicle proximal to base of the dens. The position is variable
The margins are smuuth and separated by a lucent zone (fibrocartilage?)
Slight ossociateon with Kleppel-Feil syndrome, myeoldysplasia, Morquio syndrome and Down's syndrome.
The ossicle is embedded in the transverse atlntoaxial ligment and can cause cord compression
A- comminution of both endplates. makes up 40% of burst fractures. Results from axial loading
B - fracture of superiorendplate and upper vertebral body, retropulsed posterior-superior corner. Makes up 40% overall. Results from axial load in flexion
C - Involves inferior portion of vertebral body and endplate. There is retropulsion of posterior inferior corner. Uncommon overall. Results from axial loading in flexion
D - like A but with added element of rotation
E - lateral burst fracture of axial load in lateral bend
Tumor causes diabetes insipidus in a child
Tumor causes precocious puberty in a child
optic nerve glioma
Tender swelling and increased pulsation over the carotid artery with pain in the ipsilateral neck
Usually self limited to 2 weeks or less
On imaging soft tissues around the bifurcation may enhance
Differential includes giant cell arteritis, dissection, FMD, Takayasu arteritis, carotid wall hematoma
Carotid pseudoaneurysm diff
True carotid aneurysm
Parapharyngeal space abscess
Schwannoma in the carotid space
Originates from cranial nerves IX thorugh XII, sympathetic plexus or the cervical nerve roots
It pushes the carotids anteriorly
On imaging, there is slow enhancement
There are no flow voids
On CT, hypodense
May have cysts
Arises from the carotid bulb
It splays the internal and extrnal carotids
Can grow thoughskull base to involve the carotid space
Can infiltrate the lumon of the jugular vein
On imaging there is dramatic enhancement and flow voids since this is a highly vascular tumor
Differential includes hemangioma, aneurysm, AVM, angiofibroma
Check serum metanephrine before trying angio
Derives from the nodose ganglion
Therefore pushes the carotid anteriorly
Most commonly occurs at the angle of the mandible above the hyoid.
Can invovle CN IX through XII and cause Horner syndrome
Imaging includes In 111, but there are false positives from medullary thyroif CA, thyroid adenoma, Merkell cell tumor or carcinoid.
Congenital lesions of the thyroid
1/3 are total agenesis
1/3 are ectopic thyroid, most commonly at the base of the tongue (20% of these are the only thyroid tissue) and there is 3-5% CA risk
1/3 are ectopic between the tongue and the normal location
Five segments can be defined: Intra-axial, cisternal, interdural, cavernous and extracranial (intra-orbital)
nuclei located in pontine tegmentum near midline just anterior to 4th ventricle.
Goes through prepontine cistern then into dorello canal. Over petrous apex through cavernous sinus then superior orbital fissure.
Cranial nerve 3
Motor to extraocular muscles except abduscens and superior oblique
Parasympathetic to pupillary sphincter and ciliary muscles
Four anatomic segments: Intra-axial, cisternal, cavernous and extracranial
Located in midbrain anterior (ventral) to cerebral aqueduct at level of superior colliculus
Parasaggital cortex, esp frontal lobe
Contralateral leg weak and sensory loss
Arms less so
Contralateral frontal release
MCA anterior (superior) division stroke
Primary motor and sensory
Broca's aphasia if dominant hemisphere
MCA posterior (inferior) division stroke
Total MCA stroke
Combination of both divisions
Internal capsule, basal ganglia
Pure motor hemiplegia
Possible extrapyramidal component if BG involved
Thalamus inferior medial and anterior aspects
Contralateral sensory loss
Thalamic pain syndrome
Possible movement disorder like hemiballismus and choreoathetosis
Combination of MCA and ACA symptoms
Superior sagittal sinus thrombosis
Drains hemispheres and medial cerebral cortex
Elevated intracranial pressure
Corticospinal tract sign bilateral
Transverse sinus thrombosis
Drains posterior fossa and sinus confluence
Pain esp behind ear
Elevated intracranial pressure
Cavernous sinus thrombosis
Cr nerves IV, V, VI
Possible Ophthalmic artery
Possible facial sensory loss
Possible visual loss
Acute onset headache and neurologic deficit
Nausea +/- vomiting
Stupor, coma, increased intracranial pressure
Basal ganglia hemorrhage
Putamen most common
Nausea +/- vomiting
Sudden onset come
Lost brain stem reflexes (doll's head)
Compresses brain stem too
Possible ipsilateral face weakness and decreased corneal reflex