CNS complications in ALL
Methotrexate CNS complications
Intrathecal or systemic
No specific age group
Restricted diffusion resolves with symptoms
Long term leukoencephalopathy.
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.
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.
III nucleus just posterior to red nucleus.
Passes PCOM, susceptible PCOM aneurysms.
To orbit through sup. orbital fissure.
Edinger-Wesphal nucleus = parasympathetic fibers that control iris sphincter and ciliary muscles
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 contains Gasserian ganglion, then trifurcates.
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
Superior orbital fissure
Contents: Oculomotor, trochelar, abducens, V1. Ophthalmic veins, sympathetic nerve plexus, small arteries
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.
Hypoglossal canal contents
Contents: CN XII, emissary vein, small arteries (persistent hypoglossal artery, when it is present at all)
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.
Foramen of Vesalius
Inconstant emissary foramen anterior and medial to foramen ovale.
Contents: Emissary veins
Contents: Endollymphatic duct, meningeal branch of occipital artery
Diseases: Meniere's disease, congenital stenosis, patulousness
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: Inferior alveolar nerve and vessels
Diseases: Schwannomas, Squamous cell carcinoma
Contents: Maxillary artery, Maxillary nerve, sphenopalatine veins
Diseases: Juvenile andiofibromas
Meningothelial origin tumors
Mesenchimal origin tumors
Solitary fibrous tumor
Malignant fibrous histiiocytoma
Melanocytic origin tumors
Meningioma WHO grading
Typical meningioma is grade I
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)
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.
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.
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 perineural lining or fibroblastic tissue.
Can occur after:
Nerve avulsion (C-spine)
Look like small Schwannomas on imaging.
Dural mets sources
Chunky thickening of dura on imaging.
Can even spread on top of meningioma.
Tumor of immature granulocytes associated with myelogenous leukemias.
Radiosensitive, so treat with rads.
Choroid plexus papilloma factoids
What it says. WHO I
SV40 virus implicated.
100% survival at 5 years for complete resection.
Choroid plexus carcinoma factoids
WHO grade III
Rare compared to papillomas.
About 10-20% degeneration. rate.
CSF dissemination in 60%
Can't really distinguish from benign papilloma 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
Dermoid cyst factoids
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.
Mixed density or intensity lesion. Often gross fat present.
Look for peripheral enhancing nodule to differentiate from dermoid (not a sure thing)
Juvenile pilocytic astrocytoma factoids
WHO grade I
Usually well defined, round.
Cystic with a mural nodule is classic, but may be solid.
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 factoids
Infiltrates the brain stem and therefore can not be excised.
WHO grade II, 25% survival at 10 years.
There is a tectal and exophytic type, with better prognosis.
Comprise about 1/3 of posterior fossa tumors, 50% of cerebellar tumors.
Very malignant, WHO grade IV
Melanotic type has worse prognosis.
Filum terminale best (WHO I)
Posterior fossa worst (WHO II)
High rate of seeding.
WHO grade 1
Look like ependymoma in every way except location.
Lateral ventricular arise later in life (>15 or so)
Mean age 51
Gross fat can be seen.
Otherwise look like medulloblastomas.
Pretty much the same lesion as JPA in children. Differentiate mostly by pt age.
WHO grade I, cured by resection.
Much rarer than schwannomas and mets.
25% associated with vHL
Manifestations of vHL
Islet cell tumor
Endolymphatic cell tumor
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 enhancement 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
Hemorrhage and calcification uncommon.
No cortical dysplasia
WHO grade II 80%survival at 5 years.
Similar to DNET on imaging.
Supratentorial PNET formerly cerebral neuroblastoma grading
WHO grate IV
The younger at diagnosis, the worse prognosis.
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
Usually present with seizure
Benign, Slow, Bony remodeling
Worse prognosis with higher metabolism on PE
Has some glial differentiation
No actual glial component, so no potential for malignancy unlike gangligliomas.
Desmoplastic Infantile Ganglioma factoids
Variant of ganglioglioma occurring in first 2 years
Looks like huge GBM in an infant, but much less aggressive
Dysembryonic neuroepithelial tumor DNET factoids
WHO grade 1
Neuroepithelial in origin
Looks like ganglioglioma
50% association with cortical dysplasia of some type.
Evolve from lower grades
Often predated by diffuse astrocytoma.
Mean transformation to GBM is 2 years.
Majority in the elderly are actually primary, not evolved from lower grades.
Evolved GBMs are less aggressive, younger population
Death in few months WHO IV
Syndromes associated with brain tumors
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
Corpus Callosum masses
Acute shear injury
Subependymal giant cell astrocytoma
Another glioma variant
Classically associated with tuberous sclerosis.
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 similar to central neurocytoma but age peak is different
Worse than regular oligodendroglioma
Peak mean is 49
Has everything, hemorrhage, necrosis, calcification, cystic, avid enhancing
Gliomatosis cerebri factoids
At least two lobes are diffusely infiltrated with tumor.
Lack of mass effect or distortion.
WHO Grade III
Bilateral in half of cases (half, get it?)
May degenerate to GBM with rapid growth
48% at 1 year, 27% at 2 years
WHO grade II
Slow growing, solid, well circumscribed, enhancing
Mass effect may cause hydrocephalus
Age: young edults
Well circumscribed, peripheraly enhancing, centrally necrosing. Usually large at diagnosis.
Complete resection curative
CNS lymphoma factoids
Most frequently the diffuse hystiocytic type non-Hodgkins
Often associated with immunodeficiency of some type
Can spread across corpus callosum
Usually abuts ependymal surface (toxo does not)
Can coat ventricles
Intravascular CNS lymphoma
Focal parenchymal enhancement and/or dural enhancement
Meningeal types are most frequent (Meningo, fibro, etc.)
From there invade the brain.
Acts like GBM and sarcoma rolled into one.
Favor temporal lobe with invasion of dural surfaces.
CSF seeding is common
Can have cystic component (esp if in unusual location, in which case not as radiosensitive)
Distinctly commonly hemorrhagic
Uniquely + hCG and placental lactogen.
High rate of subarachnoid seeding
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)
Pineal cyst factoids
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: Rare in CNS. Mostly in ventricles, centered on choroid
Also spinal canal, parenchymal, extra-axial
Mostly follows CSF characteristics on CT and MRI, but may be T1 bright due to debris or high protein
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 Tumor Yes Scar No
End within 3-4 days TumorYes Scar Yes
Size with time Tumor Increase Scar Decreases
Enh type Tumor Nodular Scar Solid Linear, outside bed
Mass effect/edema Tumor Increases Scar Decreases
Dural enhancement at least 1 year, sometimes many years
Granulation tissue enhancement lasts months. Suspect recurrence if still ehancing after 1 year.
Scan within 48 hours for baseline. Suspect residual neoplasm if there is enhancement
CNS post radiation changes
Early is usually reversible. Late usually not reversible
Early = within weeks
Early Delayed = within months
Late Delayed = months to years
Early ED LD
Enhancement No rare common
Long term none none vasculitis
Ca No No Yes, peds
Necro Leuko No No Rare, after 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 Tumor immediate to mths Rads Mths to yrs
Mass effect/edema Tumor Yes RadsYes
Enhancement Tumor Yes RadsYes (swiss chs)
PET Tumor Positive Rads Negative
Thal SPECT Tumor Positive Rads Negative
MRS Tumor hyper choine Rads hypo choline
Perfusion MR Tumorhyper rCBV Rads decr. rCBV
Significant extracranial ICA stenosis 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
Involves CNS about 45%, late in disease
SAH or intraparenchymal hemorrhage occurs
! Aneurysms are unusual in the CNS
CNS giant cell arteritis
Rapid vision loss when ophthalmic artery occluded suddenly. Headache common.
Intracranial involvement is rare.
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
Mechanism possibly spasm or thrombosis.
Bleeds from hypertension
Intracranial arteritis (Heubner arteritis)
Focal defitis and encephalopathy
Usually 6-8 years after onset of disease
Retinocochleocerebral vasculopathy factoids
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.
Preference of brain stem and diencephalon.
Narrowing, 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 parenchymal hemorrhage predominates.
On MRI, low flow in distal ICA, and flow voids in basal ganglia representing dilated collaterals.
Can have cerebrovascular occlusive 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 vasa-vasorum, resulting intimal and medial hyperplasia narrowing and eventual occlusion of LARGE vessels.
Anterior and middle cerebral arteries most often involved, posterior circulation 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 of hemorrhage
Time T1 T2 stuff
Hyperacute <6 Hr Dark Bright oxy Hb
Acute 8-72 hr Iso Low deoxy Hb
Early sub 3-7 days High Low Intra MetHb
Late sub >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, just in 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 associated with aneurysm
Too many to write them all
All the intracranial vasculitides.
Familial idiopathic nonarteriosclerotic cerebral calcification syndrome
Hereditary hemorrhagic telangiectasia.
Aneurysm source by bleed location
Interhemispheric fissure and lateral vent-AComm
4th ventricle- PICA
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.
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
Capillary telangeactasia factoids
Mass of telangiectatic vessels in the brain
Variable size, average 3 cm.
Between the vessels is NORMAL tissue
enhancing nodule in Pons
Cavernous angioma factoids
Are congenital vascular hamartomas
There is NO interposed normal brain tissue.
May be surrounded by gliosis.
Predilection for cerebral hemispheres and brain stem.
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 early draining vein and blush or persistence of aberrant veins.
Propensity for pariventricular area.
Most are asymptomatic and do not bleed.
Drains normal brain parenchyma. Venous infarction can follow if this runoff is closed off.
Has one or more enlarged feeding arteries and enlarged 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.
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.
Look for many lesions of different ages (by blood age)
Can have any type of bleed, 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.
Epidural abscess factoids
Usual route is from mastoids or paranasal sinuses into the epidural space.
Syphilis is just about the only primary cause.
Can cross midline but confined by sutures like epidural hematoma
Subdural empyema factoids
Same as an abscess, but in the subdural space.
Much more common than epidural.
Tratment is drain with wide craniotomy
Most often by direct extension. Hematogenous spread is less common.
Usual presentation with headache, stiff neck
Spectrum of meningitis or postoperative.
Can present with enlarge ventricles, enhancing ependymal rim. Possible choroid enhancement.
Periventricular calcification can occur after the fact.
Pitfall-ependymal enhancement also occurs in HIV related lymphoma or malignancies spread subependymally.
Choroid plexitis factoids
Hemorrhagic seeding due to high vascularity.
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 zoster
Tends to occur in immunosuppressed (Particularly with lymphoma) or elderly population.
Caused by reactivation of the dormant virus.
Can have involvement of ophthalmic nerve, can even infarct.
Vasculitis with multiple segmental constrictions.
Shingles associated with ipsilateral posterior column atrophy.
Aggressive early treatment with acyclovir.
Can also cause meningitis, ventriculitis.
Postvaricella encephalitis imaging
Bilateral symmetric high T2/FLAIR regions without enhancement.
ADEM is major differential.
Subacute sclerosing panencephalitis factoids
A secondary demyelinating disease of viral etiology.
Slow viral infection post measles, particularly if before 18 months.
Marked elevation of gamma globulin on CSF labs, measles antibodies.
Disease is Infectious mono. Can also have Guillan-Barre, mutiple CN palsies.
Brain stem tumor
Eastern equine encephalitis
Short prodrome then
AMS, SZ, focal deficits.
Periventricular and cortical are less common
None are specific
Japanese encephalitis factoids
Throughout Asia, mosquito borne virus
Rapid progression to coma after predictable fever, headache, ams. Can have extrapyramidal signs.
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 symptoms), most often in basal ganglia.
AIDS dementia complex factoids
Involves WM and deep gray
Diffuse pallor of centrum semiovale, atrophic changes.
No real correlation to state of immunosuppression.
Toxoplasmosis vs Lymphoma imaging
Important to differentiate from Lymphoma. Delaying treatment for either is bad. Mistaken toxo treatment believed to decrease efficacy of radiation on lymphoma.
High density mass on non-contrast CT, or ventricle
T2 hyper, hemorrhage, ring lesion better for Toxo
Encasement of vessels, iso on T2, thallium take-up better for lymphoma.
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)
CNS TB factoids
Usually carried into brain by hematogenous seeding, but 19% have no evidence extrameningeal disease at time of diagnosis.
Can lead to intracranial tuberculoma
Can manifest with CN palsies
Aggressive treatment with ABx and follow-up imaging to gauge response.
Usually negative for organisms
Gm + rod
Causes meningitis, meningoencephalitis. Rarely abscess.
No specific appearance, but likes brain stem (rhombencephalitis)
Likes impaired cellular immunity, diabetics, alcoholics, post-transplant.
Nonspecific T2/FLAIR lesions can be small to large and can enhance.
Can involve parenchyma, 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
Same process as widened VR spaces can dilate basal cisterns, 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.
Most vulnerable are
diabetics with ketoacidosis
debilitated with burns
People on iron chelator deferoxamine also apparently vulnerable
Fungus rapidly destroys mucosa leaving black eschar
Aerobic fungus resembling actinomyces, 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
Infects the immunocompromised.
CNS spread by inoculation or hematogenous seeding from pulmonary nidus, extension from sinuses.
Aggressive in the CNS, producing meningitis, meningoencephalitis, hemorrhagic infarction.
If less aggressive, can make abscess or isolated granulomas.
Likes neutropenics on steroids.
Gets to CNS by hematogenous spread
Causes vascular inflammation, thrombosis, infarction, microabscesses. Possibly noncaseating granulomas.
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)
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.
Usual presentation is seizure.
Cyst and scolex develop after several weeks after infection.
Symptom onset average is 4.8 yrs (1-30)
Symptoms are site dependent
Ventricular can result in hydrocephalus or granular ependymitis.
Rare, only a bout 2% of cases.
Involves CNS by occlusion 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.
Migrating adult tapeworm.
In CNS causes
Chronic granulomatous lesions with cerebral atrophy, organizing 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%
Severe chemical encephalitis results from cyst rupture
Sarcoidosis CNS involvement
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 leptomeningitis
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.
parenchymal sarcoid nodules
associated with extensive arachnoiditis and
microscopic granulomas throughout
obstructive hydrocephalus if in periaqueductal
Nodules act like intracranial mass
High intensity WM
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
CNS Behcet's factoids
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
Venous thrombosis common
Granulomatous disorder due to delayed immunity to bacterial agent.
CNS involved in 20%
Can be aggressive leading to coma and death
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
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.
Acute necrotising encephalopathy of childhood factoids
Age 5 mths to 11 years (asia)
Occurs after infectious encephalitis episode
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
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
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.
Brain abscess factoids
May present with seizures, altered mental status, and focal neurologic deficits.
Key point: Contrast enhanced imaging demonstrates a well-defined, thin walled, enhancing rim.
Usually thicker on gray matter side.
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 thrombus or embolus is slowly lysed, eventually 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 collaterals, which takes about a week to develop.
On autopsy, about 40% of infarcts are actually hemorrhagic to some degree (maybe patechial)
Cerebral amyloid angiopathy factoids
NOT amyloid in tissue.
The amyloid is deposited in the media and adventitia of small and medium 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 is usually lobar, frontoparietal.
Can present as subdural or subarachnoid.
Propensity for multifocal and recurrent hemorrhages.
CADASIL stands for
Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarction and Leukoencephalopathy
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
Vascular demyelinating diseases
Subcortical infarction and leukoencephalopathy
Metabolic demyelinating diseases
Combined systemic diseases B12 deficiency
Peak age range 30 years
Symptoms: Cranial nerve palsy, optic neuritis, vague sensory complaints progressing to paresis, paraplegia of limbs, myelopathy.
Course can be relapsing remitting, secondary progressive (relapsing progressive), Primary progressive (seems to have fewer imaging lesions despite progressive course). Malignant type is rapid progressive.
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.
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 mechanism is cell mediated immunity to myelin basic protein
Symptoms similar so a singe episode of MS
ADEM can enlarge spinal cord or brain stem, but usually seen in cerebrum
Rare fulminant variant = Hurst's disease
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.
May be solitary or multifocal
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
Conditions associated with PML
Immunosuppressive therapy for other
Post anoxic encephalopathy factoids
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.
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 facts
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.
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
Path: axonal swelling, multifocal demyelination, coagulation necrosis, gliosis
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
Autosomal recessive. Due to deficiency of aryl sulfatase A, which hydrolyzes sulfatides to cerebrosides.
Myelin is not 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 with 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.
Caused by acyl-CoA synthetase preventing breakdown of very long-chain fatty acids with accumulation in white matter, adrenal cortex, plasma and RBCs
Vanishing white matter disease
Seen in children and teenagers.
Cortex is relatively normal.
White matter is largely destroyed with exception of some sparing of U fibers.
CRASH syndrome stand for
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.
External hydrocephalus factoids
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.
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.
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.
Exclude dural venous malformation or venous thromboses as cause, these can have high morbidity if missed.
LP demonstrates extreme elevations of CSF pressure .
Treatment is repeat LP. Spontaneous remission is frequent. Shunting may be necessary. Diuretics and carbonic anhydrase inhibitors can help
Frontotemporal dementia variants
Semantic variant: 40% of total.
Temporal lobe atrophy and parahippocampal regions. Hemispheric asymmetry, left more 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 factoids
Parkinson's like features plus severe supranuclear ophthalmoplegia (impaired downward gaze), gait disorder, dysarthria, postural instability and pseufobulbar palsy few years after initial onset.
Patients present with hyperextension of the neck, contracted facial muscles resulting in "surprised look".
Cortical-basal ganglionic degeneration definition
Neuronal loss in SN, frontoparietal cortex and striatum.
Presents with postural instability, dystonia, akinesis, apraxia, myoclonus, bradykinesia, limb rigidity.
Rare autosomal recessive disorder affecting bile acid synthesis.
Deficiency causes elevated cholesterol levels, tendinous xanthomas, early cataracts, diarrhea, osteoporosis, polyneuropathy, spasticity.
Occurs in childhood.
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 differential
Hypoxic-Ischemic Injury, NOS
Congenital Infections (HIV, CMV)
Endocrinologic Disorders (Hyperparathyroidism, Hypoparathyroidism, Pseudohypoparathyroidism, Pseudopseudohypoparathyroidism, Hypothyroidism)
Radiation and Chemotherapy
Cerebellar atrophy causes
Alcoholic cerebellar degeneration
Drugs, e.g. phenytoin
Multi system atrophy (MSA) 4
Fahr disease: atrophy not specific to cerebellum
Paraneoplastic cerebellar degeneration (PCD)
Olivopontocerebellar atrophy (OPCA) 6
Marinesco-Sjögren syndrome (MSS) 5
Occurs in young adults
Associated with cerebellar and brain stem atrophy
Pons, inferior olives, cerebellar peduncles are strikingly small.
Marked cerebellar atrophy, particularly vermis.
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 factoids
Distinct from Friedrich ataxia. Produces dramatic cerebellar atrophy.
Seen in middle aged patients with severe vermian atrophy and lesser involvement o the remaining cerebellum.
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.
Death usually in childhood.
If surviving to adulthood-high risk of multiple organ cancers.
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.
Mitochondrial Encephalomyopathy, Lactic Acidosis, Strokelike episodes
Is a rare mitochondrial disorder.
Lesions can cause cortical blindness.
Eventually posterior cerebral atrophy develops.
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
disorder of alpha mannosidase
Low dnsity in parietooccipital white matter, atrophy, thick skull, lenticular opacities, brachycephaly, craniostenosis
3-hydroxy-3-methylglutaryl-coenzyme Amylase deficiency
What, no dead white guy name?
Problem with leucine metabolism
Macrocephaly with open opercula and abnormally high signal in basal ganglia esp globus pallidus.
May present with encephalitis.
Methylenetetrahydrofolate reductase deficiency
A type of hyperhomocysteinemia. Most mutations are mild and 40% of Americans are carriers.
Very rare mutations can cause severe hyperhomocysteinemia
MR: severe atrophy and hypomyelination
MRS: reduced NAA
Treatment is folate supplementation.
Cystathionine beta synthase deficiency.
CBS gene Chromosome 21q22
Maple syrup urine disease factoids
Branched chain amino acid disorder
At least 3 different genes must be affected, which usually work in a complex.
Propionic ecidemia, Methylmalonic ecidemia factoids
Both affect tricarboxylic cycle
Both lead to metabolic acidosis.
High frequency in Saudi Arabia - autosomal recessive
Trends of myelination birth-2 years
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 diasteatomyelia.
Ventral induction disorders etiology
Main anomaly is holoprosencephaly
Since premaxillary facial structures are associated with ventral induction, there are common defects such as cyclopia and probosci
Results from overproduction of neurons
Associated with achondroplasia, Soto syndrome, Beckwith-Wiedemann
Arachnoid cyst factoids
Distinguishing feature: Cerebral veins are displaced inward (they are on the inner leaflet of arachnoid) unlike subarachnoid collections. Scalloping is not seen in hygromas.
Rathke cleft cyst factoids
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
Meninges protrude through skull or spinal canal and include neural tissue.
Interestingly meningoencephaloceles are more common than meningoceles.
Associated with Chiari II in occipital region.
Followed by 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 a nasal polyp (and removal attempted).
Often diagnosed on obstetric US when no brain is seen.
Elevated alphafetoprotein 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 lobes, 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.
Maximal hydrocephalus is a main differential. Look for a well formed falx, cortical mantle plastered against the skull and separated ventricles.
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 growth hormone)
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.
Agenesis of Corpus Callusom
Fairly common (about 0.7% of live births)
When splenium is gone, there is physical appearance of colpocephaly.
In complete agenesis, there is high riding posteriorly oriented third ventricle with parallel and widely spaced lateral ventricles. There are Probst bundles.
CNS Hamartoma imaging
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 involves gray matter,
located in the wrong place due to abnormal migration in 7th to 16th weeks of gestation.
Incomplete lissencephaly. Characterized by short broad fat gyri caused by abnormal sulcation and gyration of the cortex. White matter is increased.
The insult is likely a 12-24 weeks.
Neuroblastic migration does not progress 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.
Possibly X linked
Possibly due to ischemic laminar necrosis of the 5th cortical layer after 20th week of gestation. By this time neurons have reached the cortex.
CMV infection is implicated but not proven. Other infections also being investigated.
Congenital bilateral perisylvian syndrome factoids
Polymicrogyria involving opercular cortex associated with abnormal sylvian fissure sulcation.
Abnormal sylvian fissure 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)
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.
Similar manifestations to neurofibromatosis and encephalocraniocuaneous lipomatosis.
Can present with hemimegalencephaly, 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).
They do not grow. Symptomatic only secondary to other associated defects. 50% associated with agenesis of corpus.
Tare entity consisting of loss of cerebellar hemispheric separation with fusion of the hemispheres through the midline.
There is no anterior vermis.
Dentate nuclei and middle cerebellar peduncles are fused.
Deficiency of posterior vermis.
May also have agenesis of septum pellucidum.
Males > females
Asymmetric skull due to partial premature suture closure is Plagiocephaly.
Brachycephaly (short fat head)
Autosomal dominant or recessive (recessive is worse as usual)
Calvarial involvement frequent in both
May cause foraminal herniation of tonsils due to lack of space in posterior fossa.
Achondroplasia CNS factoids
Small foramen magnum
Short clivus, platybasia,
J shaped sella.
Spinal stenosis due to short pedicles.
Flattening of the skull.
Present when the basal angle formed by intersecting lines from the nasion to tuberculum sellae, and from tuberculum along the clivus to anterior aspect of foramen magnum is greater than 143 degrees.
Associated with Klippel-Feil, cleidocranial dysplasia and achondroplasia.
Congenital Rubella characteristics
Migration anomalies (rare)
Parenchyma: necrotic foci, delayed myelination
Basal ganglia and cortex calcifications
Other: Patent ductus, pulmonic stenosis, rash, hepatosplenomegaly
Congenital herpes simplex encephalitis characteristics
Clinical: skin lesions
Ocular: chorioretinitis, microphthalmos
Head size normal
Parenchyma: Hydranencephaly possible
Patchy areas of low density in cortex and WM, encephalomalacia, cortical laminar necrosis.
NO PREDILECTION TO TEMPORAL LOBE unlike the acute encephalitis.
Congenital Toxoplasmosis characteristics
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.
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.
associated with microcephaly
Parenchyma: glial microglial nodules in basal ganglia, brainstem, WM. Demyelination, atrophy, corticospinal tract degeneration.
Vasculitis with calcifications.
Other: neck adenopathy, oral candidiasis.
Absent nasal septum differential
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 structures affected more.
Deep gray structures become hypodense on CT, hyperechoic, bright on T1. Contrast enhancement is a bad sign
Partial asphyxia in premies characteristics
Classical pattern of periventricular lekomalacia: White mater insult 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.
Partial asphyxia in term infant characteristics
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 lesions alone are not predictive of cerebral palsy
Germinal matrix hemorrhage factoids
Occurs in premature infants in the immature germinal matrix.
90% occur within the first week.
Thought to be venous in origin.
Congenital vascular malformation in brain
The only one that presents in infancy is vein of galen aneurysm.
Tremendous shunting causes 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 factoids
Common source of seizures in adolescents 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.
NF1 CNS lesions
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.
Strongly associated with NF1
Sheets of collagen and Schwann cells that spread aggressively insinuating around a nerve in circumferential manner.
The mass is soft and elastic, is the cause of elephantiasis.
Higher rate of malignant transformation than regular neurofibroma, and a lot higher than schwannomas.
Fewer skin lesions than NF1, but tends to be bilateral.
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
Tuberous sclerosis factoids
Most frequently is a sporadic mutation, but can be autosomal dominant (less common)
Associated with cortical heterotopias and ventriculomegaly.
Most periventricular subependymal nodules are calcified, but only 50% of the parenchymal ones.
Hamartomatous proliferation of meningeal cells via blood vessels into cerebral cortex.
Leptomeninges are thick and infiltrated with fibrous tissue. May be calcified.
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.
Melanoblasts from neural crest cells present in globes, skin, inner-ear, sinonasal cavity, leptomeninges are source.
Characterised by cutaneous nevi, melanotic thickening of meninges.
May lead to hydrocephalus, cranial neuropathies and syringohydromyelia.
Longitudinal split in the spinal cord. Split may involve all layers of meninges resulting into 2 dural sacs. Two hemicords in one sac are more common though.
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.
Caudal regression syndrome
Truncated blunt spinal cord in the lower thoracic level associated with incomplete formation of sacrum and genitourinary tract.
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 the 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 central canal dilation or a cavity eccentric to the central canal.
Mostly associated with congenital malformations including the Chiari spectrum and myelomeningoceles. May also arise due to trauma, ischemia, adhesions, neoplasms.
Pitfall-dilated central canal in conus medullaris (5th ventricle), a normal variant.
Anastamotic pathways between internal and external carotid
All go through ophthalmic artery from internal carotid
On the external carotid side
Superficial temporal: Supratrochlear 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
Has a rare diffuse infiltrative form, without a mass.
Mets usually occur within 2 years of treatment.
Often occurs in the pineal (the third eye also third testicle), in which case associated with bilateral type.
Persistent hyperplastic primary vitreous
Persistence of portions of the primary vitreous with hyperplasia of associated embryonic connective tissue. May present as leukokoria.
Funnel shaped mass of fibrovascular tissue including hyaloid artery persisting in the retrolental space. Runs in S shaped course through Cloquet canal between back of lens and head of optic nerve.
! Does not calcify unlike retinoblastoma!
CNS Toxocara canis infection
Child ingests 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 vitreous opacification and retinal detachment.
The ocular lesions occur months to years after initial infection. The chronic endophthalmitis causes unilateral leukokoria.
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.
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 primitive 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 rim and retrobulbar extension.
Choroidal osteoma factoids
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.
Occurs in up to 40% of adults with a subarachnoid hemorrhage, 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 globe secondary to surgery, trauma or glaucoma therapy.
May be observed 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 choroidal detachment
Hemorrhagic detachment does not change location with position.
Retinal detachment factoids
Sensory retina is detached from pigment epithelium
V shape with apex at optic disk
May extend to ora serrata
Choroidal serous 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
Posterior hyaloid space detachment
Separated posterior hyaloid membrane from sensory retina
Thin semilunar shapes with dependent layering
Posterior globe configuration changes to look conical like a tent.
Caused by intraorbital mass lesion producing proptosis with tethering of the globe by the stretched optic nerve.
Posterior scleritis factoids
Infectious (any type, bacterioal, fungal, viral) or
Autoimmune (usually collagen vascular diseases)
Can be acute or chronic
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. Usually unilateral.
Classified as typical or atypical depending on location and derivation.
Atypical form: Occurs in iris.
Typical is cone shaped notch 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.
Grows slowly, does not metastasize.
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
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 mitochondria from disrupted axons serve as substrate for calcium deposition.
May progressively enlarge over years.
Associated with retinitis pigmentosa.
Located at junction of optic nerve and globe.
Optic neuritis factoids
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 sufferers already have WM lesions on MRI.
Optic nerve glioma
Is a juvenile pilocytic astrocytoma.
Represents 2/3 of pall primary optic nerve tumors.
Growth phase during childhood, causing them to become symptomatic, then stabilize in most, but indolent progression in 40%
Decreased vision is an early sign in meningioma, 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.
Optic nerve sheath meningioma
Usually form meninges of the nerve, but can extend from cranial meninges.
Can be diffuse tubular, fusiform, globular perioptic and nerve may even be separate from tumor mass.
When associated with NF, also look for pneumosinus dilatans of sphenoid, blistering of the planum sphenoidale.
Cavernous or capillary.
Consists of dilated endothelial lined vascular channels in a fibrous pseudocapsule.
Grows very slowly and can even stop, but can grow rapidly in pregnancy (hormone dependent?)
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 malformation 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 or many varicosities.
Proptosis and enlargement of veins brought out by Valsalva maneuver or coughing.
Usually congenital. Also can occur from trauma.
Orbital lymphangioma factoids
Dysplastic 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.
Tendency to hemorrhage bringing about acute onset of symptoms.
Carotid cavernous fistula
Direct communication between intracavernous portion carotid to venous cavernous sinus.
Causes enlargement of extraocular muscles, proptosis, dilation of the superior ophthalmic vein (unilateral, as opposed to bilateral in case of diffuse cerebral swelling)
Conjunctival edema causes periorbital swelling and blurring of globe margin.
Cavernous sinus dural malformations
Not usually traumatic in origin. Instead linked to venous thrombosis.
Symptoms less fulminant. Can have periocular pain. Cranial Nerve 3,4,6 palsies, visual loss (6th nerve due to compression of Dorello canal)
Common cause of unilateral exophthalmos (contrast to graves, which is mostly bilateral)
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.
Thyroid ophthalmopathy factoids
85% bilateral, only 5% unilateral, 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.
Orbital sarcoid factoids
Common, up to 25% of all sarcoid cases, but isolated orbital disease is rare, usually in lacrymal glands
Granulomatous inflammation, 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.
Orbital involvement usually late, produces pain, proptosis, erythematous eyelid edema, limited movement.
Orbital lymphoma factoids
Can be primary orbital, or extension from systemic.
Generally in older population.
Presents with slow, progressive painless periorbital swelling and low grade proptosis.
PTLD in orbit factoids
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 skin and subcutaneous soft tissues
No proptosis, disturbance of movement or chemosis
No abnormality posterior to orbital septum on CT and MRI.
Postseptal cellulitis factoids
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
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 occurring after obstruction of sinus ostia. Presents with diplopia and proptosis if extends into or near orbit.
There is bowing and thinning of bone without breakthrough.
Can rupture, causing granulomatous reaction and scarring.
Most often located in superolateral portion of the orbit at frontozygomatic suture near the lacrimal fossa.
Orbital rhabdomyosarcoma factoids
Primary tumor arises from primitive orbital mesenchymal elements.
Secondary involvement is by extension from extraocular muscles, nasopharynx, paranasal sinuses.
Orbital fibrous histiocytoma factoids
makes only 1% of primary tumors here
Mostly benign, but can be locally aggressive.
Orbital mets factoids
Most are extraconal, but invade with enlargement or compress the cone.
Average survival after presentation is 9 months, so a late, bad finding.
Orbital neuroblastoma imaging
High density on CT and lack of preseptal extension (as opposed to rhabromyosarcoma)
Anatomy of cavernous sinus factoids
Subdivided into intracavernous and intradural compartments.
Drains into superior and inferior petrosal sinuses.
Basilar venous plexus in the dura behind clivus provides lots of other connections.
Makes the lateral wall of the sella.
Pituitary anatomy factoids
upper surface flat or slightly concave.
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.
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 disturbances (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.
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.
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 (hanta virus), which causes pituitary necrosis or atrophy with visual field defects.
Make up 1.8-12% of pituitary lesions
Often clinically silent, picked up incidentally.
Inflammatory disease of the pituitary involving the infundibulum.
Can be associated with deranged hormone levels, including diabetes insipidus.
Pinching of stalk by tight diaphragma sella may compromise blood supply to posterior pituitary. Bright spot is often gone.
Posterior pituitary tumors
Choristoma is composed of normal cells in wrong location, but not local cells (Hamartoma is overgrowth of local cells in wrong organization)
May produce 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 suprasellar and in 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
Differential for this is chiasmatic/hypothoalamic glioma.
Diabetes insipidus is common association of any pituitary/stalk lesions
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, occurring mostly in adults.
Mass lesion in suprasellar cistern.
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.
May be pedunculated
Arise from primitive germ cells.
Mass lesions can be locally invasive.
May coexist with a proper pineal lesion.
Mets by subarachnoid seeding.
Nasopalatine duct cyst factoids
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.
Likely remnants of the embryonic nasopalatine duct
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.
Cavernous sinus thrombosis association
Associated with sepsis or with dural malformations. Also from surgical or interventional procedure.
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 predominantly in the middle cranial fossa, region of gasserian ganglion (sits in meckel's cave) or posterior fossa.
Can be dumbbell shaped (least common).
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 other 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.
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),
replacement of normal CSF density and intensity in the trigeminal cistern (Meckels cave),
a mass in the cavernous sinus,
atrophy of the ipsilateral masticator muscles.
Skull base chondrosarcoma clinical
Symptoms are location dependent. Most will have had headaches and intermittent cranial nerve palsies (particularly IV).
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.
Congenital malformations of the EAC
Are more common than of the inner ear.
Minor microtia or major microtia, coexists in 73%.
Stapes abnormalities present in up to 70%.
Some cases due to congenital Rubella.
EAC atresia is bilateral in about 1/4 cases.
EAC atresia, horizontal portion of facial nerve may have aberrant course.
Keratinous plugs and cholesteatomas may form.
Malignant otitis externa
Most severe inflammatory condition affecting the EAC.
Is caused by Psudomonas infection.
Presents with foul smelling purulent discharge.
Starts at junction of bony and cartilaginous portion of EAC, along fissures of Santorini
Activity on gallium citrate scan.
Congenital abnormalities of the middle ear factoids
may coexist with abnormalities of the facial nerve
Not as common as abnormalities of the external ear.
Most are due to strep, Moraxella catarrhalis, H influenzae, pneumococcus.
In children, obstruction of the eustachian tube outlet can lead to otitis media.
Dislocation of ossicles
Can be caused by trauma or infection.
Suspect when there is more than 1 mm distance between long process of incus and the head of the stapes.
Incudal disarticulation accounts for more than 80% of post-traumatic conductive hearing loss.
Infection introduced from middle ear via the aditus ad antrum, the channel 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.
Usual organisms are beta hemolytic strep and penumococci.
Acquired cholesteatoma factoids
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
Pars tensa cholesteatoma factoids
Much less common than the acquired pars flaccida ones.
Scutum usually intact.
Glomus tympanicum factoids
A variant of the glomus tumor, this one occurring in the ear.
Arises from paraganglion tissue in the middle ear.
Persistent stapedial artery factoids
Rare, <0.5% incidence
When persists, can present as a pulsatile middle ear mass.
Glomus jugulare factoids
A paraganglioma arising from tissue in the jugular vein near 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 origin
Commonly affect the transverse sinus and in some cases may be due to previously thrombosed veins or sinuses.
Can cause pulsatile tinnitus in the right location
Facial nerve schwannomas factoids
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.
Distinguished from schwannomas only when there is extensive calcification or when there is enhancement.
Without calcification also think glomus tympanicum.
Malignant lesions in the middle ear differential
Usually arise from EAC structures which then invade the middle ear.
Think squamous cell carcinoma,
rhabdomyosarcoma (by extension or primary),
salivary gland tumors from ectopic rests (adeno, adenoid cystic carcinoma).
Inner ear congenital abnormalities
Structure develop 4th-10th weeks.
Also cochlear aplasia and hypoplasia, where cochlea may fail to form at all.
Cochlear aqueduct congenital enlargement may result in hearing defect.
Abnormal connection between the subarachnoid space and the perilymphatic space of the inner ear.
often associated with stapes malformations
Fistula can provide easy tract for spread of middle ear infections to meninges.
Semicircular canal abnormalities factoids
A form of otic dysplasia.
Somehow results in hearing loss rather than balance problems.
compensatory enlargement of the vestibule.
Associated with CHARGE syndrome.
Superior semicircular canal dehiscence is characterized by sound and or pressure induced vertigo (Tulio phenomenon)
Vestibular aqueduct abnormalities factoids
Also seen after trauma.
Enlarged vestibular aqueduct causes high frequency hearing loss.
May be isolated or associated with other defects
Atresia is associated with absence of CN VIII and VII
congenital anomaly that is a manifestation of the split notochord syndrome.
typically extend over three segments.
may have an extraspinal component, located in the mesentery or mediastinum
Oscillopsia and lound noise induced vertigo.
Occurs in otosyphillis, Meniere disease, Perilymphatic fistula, Lyme disease.
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
Labyrinthine ossification factoids
Many causes including trauma, infection, syndromes
results in deafness and/or vertigo
Cochlear otospongiosis factoids
Is defined as replacement of enchondral bone by spongy bone.
A cause of bilateral sensorineural hearing loss, ~80% of cases.
Cochlear deminiralization in a child causes
Can be seen in
Causes of labyrinthine ossification
Cholesteotoma with labirinthine fistula
Chronic otitis media
Late or treated otospongiosis
Fenestral otospongiosis factoids
A more common form than the cochlear type
Causes conductive hearing loss.
Both spongiosis and plaques narrow the round window niche
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 periphery moving centrally, as compared to cochlear otosclerosis which follows the reverse course, central to peripheral.
There is an autoimmune type, which is usually bilateral.
Diff: Labyrithine schwannoma
Dense temporal bones differential
Congenital hypoplasia of the mastoid
Petrous apicitis factoids
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
The cause is thought to be rupture of a small vessel with recurrent hemorrhage, which elicits a foreign body response with giant cell and fibroblastic changes and cholestrol crystal collections.
THIS IS NOT A CHOLESTEATOMA
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.
Associated with vHL syndrome.
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 hemotympanum seen in about 50%
Horizontal temporal bone fracture
Traverses the EAC, middle ear and often sphenoid bone.
15-20% are associated 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 subtle 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.
Presents as respiratory distress while feeding
Membranous atresia accounts for 15%, bony for the rest.
Association with congenital CNS malformation in about 50% cases.
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 no connection to the brain.
Treated with surgical excision.
Hypoplastic maxillary antrum
The antral roof is down-sloping, with an enlarged ipsilateral nasal cavity, low ipsilateral orbital floor and thick lateral antral wall
About 9% frequency in population.
Differential: Silent 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.
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 for periantral 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 increased CT density in the sinus, which is decreased intensity on T2.
Cystic fibrosis head and neck
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 normal pneumatization.
Polyposis of sinuses factoids
Allergic or hyperplastic
Can be associated with aggressive bony destruction
Most cases are bilateral (>80%)
Occurs in 1.3% of general population and 16% of chronic sinusitis sufferers.
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
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
Associated with squamous cell carcinoma in 15% of cases
Benign, but can locally aggressively destroy bone, cross the cribriform plate into the skull.
Staging of inverted papilloma
I - limited to 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 factoids
Makes up about 80% of paranasal sinus malignancies
80% have bony destruction at presentation
Enhancement of the dura does not imply neoplasm. almost any inflammatory process with make the dura enhance.
Signs 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
Often involve adjacent structures, even extending to calvarium
Minor salivary gland tumors of sinus
Has propensity for perineural spread.
Imaging: variable T2 signal
Associated with melanosis
Propensity for perineural spread. Metastasises easily by hematogenous spread
Has a propensity to cross the cribriform.
Can metastasize hematogenously or by lymphatics.
Associated intracranial cysts are pathognomonic.
Imaging: low T2 signal.
Lymphoma of sinonasal region
Mostly non-Hodgkin type
Occurs mostly in the sinuses
Can be result of PTLD
Arises in the apposition of mucosal surface in the midline.
Can get infected on occasion and can be a source of persistent halitosis.
Nasopharyngeal inflammatory lesions
Adenoidal hypertrophy of HIV
Infected Tornwalt cyst
Mucus retention cyst
Tonsillitis of the adenoids.
Torticolis with rotatory subluxation of C1 on C2 secondary to adjacent inflammatory mass.
Can be caused by pharyngitis or retro-pharyngitis.
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)
This is the predominant nasopharyngeal tumor in children.
It is very responsibe to chemo
Intracranial extension is common.
Commonly presents with rhinorrhea.
Common locations include nasopharynx and palatine tonsils
Imaging: Oval mass iso in T1 and iso- to slightly hyperintense 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
Occurs in setting of
familial fibrous dysplasia of mandible,
SAPHO stands for
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 minor 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
Presents with expanded jaw, but painless unless infected.
Often associated with dentigerous cyst
Has a high recurrence rate.
Brown tumor of mandible
Lytic erosion of lamina dura,
poorly defined mass.
Central odontogenic fibroma of mandible
Multilocular lesion with sclerotic borders and expanded mandible
Lytic, lucent lesion adjacent to an unerupted tooth, which spares the cortex.
The margins are sclerotic.
Most frequently at an unerupted 3rd molar or canine.
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 attached to mandibular tooth
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)
Rate increase with age, as does the size
Develops at the natural Killian's dehiscence between the cricopharyngeus and inferior pharyngeal constrictor.
This is a lateral diverticulum
Overall smaller than Zenker's and occurs at any age.
Congenital lesions of the larynx
occur at the level of true cords
Laryngeal submucosal cyst
Due to obstruction of a minor salivary gland.
Common location is in supraglottic
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 occurring 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
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
Imaging: exophytic or submucosal enhancing mass
Rare complication after a standard therapeutic radiation dose to the larynx.
Presents with soft tissue swelling and sloughing 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
Spindle cell sarcoma of the larynx
Has characteristics of both squamous cell and sarcoma on histology
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 clinical
Cause swallowing and gag reflex dysfunction, pharyngeal muscle atrophy, deviated uvula
Vocal cord paralysis signs
There is cord atrophy
Dilation of the laryngeal ventricle
Medial 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 decreasing order of size
Most are apparent at birth
Can be diagnosed in utero when large enough to be a cause of polyhydramnios.
Can spontaneously hemorrhage.
The lesion is compressible and distorted by arteries.
A classic cause 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
Presents with multiple enlarged non-necrotic nodes.
The Waldeyer ring is hypertrophied (also happens in AIDS)
Perinaud oculoglandular syndrome
polypoid granuloma of palpebral conjunctiva and
periauricular, parotid and periparotid lymphadenopathy.
Caused by Bartonella, same as cat scratch disease
Histiocytic necrotizing lymphadenitis
Patient usually young and Asian descent
There is adenopathy, fever and leukopenia.
Chronic inflammation with diffuse hypervascular adenopathy in the cervical chain, predominantly level I.
There is eosinophilia.
The salivary glands can also be swolen and tender.
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
Can be retropharyngeal or hemorrhagic. Basically any appearance at all.
Adenopathy due to Lymphoma
Usually non-Hodgkin type in the head/neck region.
But this is actually the 2nd most frequent region for NHL after the GI tract.
Often ivolves Waldeyer ring.
With a history of Mononucleosis, Hodgkin type is more likely.
Hodgkin type seems to progress orderly from one chain to the next.
Non-Hodgkin type leaps around haphazzardly
Duct of Bartholin
A dominant sublingual duct that opens to the Wharton's duct and drains the sublingual gland.
Cystic masses of the parotid gland
Branchial cleft cyst
2nd branchial cleft cyst
Makes up the majority of BCCs, ~90%
Usually located anterior to mid sternocleidomastoid deep to the ICA at angle of mandible
Drains to parapharyngeal basilar fossa or skin
3rd branchial cleft cyst
Most lie in the posterior cervical space, posterior to the sternocleidomastoid muscle
Occasionally can have retropharyngeal extension
(for accurate diagnosis, the relationship of the sinus tract to the superior laryngeal nerve must be determined surgically).
Autoimmune chronic sialadenitis
Presents with truncated main ducts with punctate globuloar collections peripherally in the gland parenchyma
Painless enlargement of salivary glands, usually parotid.
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 with 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 main salivary duct system
Imaging: MR punctate, globular, cavitary, destructive appearance of ducts associated with lymphoepithelial cysts and nodules.
Differential: lymphoepithelial lesions of HIV
Pleomorphic adenoma of parotid
makes up over 80% of benign 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)
They look similar to pleomorphic, but more common in submandibular gland (as opposed to pleomorphic, more common in parotid)
aka cystadenoma lymphomotosum.
Can be cystic or lymphoma like (hence the name)
Nearly exclusive to the parotid.
May have a tumoral cyst, which favors the parotid tail
There is no malignant potential
Rare, benign, exclusive to the parotid gland
MR characteristic similar to pleomorphic adenoma
Hot on scintigraphy
Hemangioma of salivary gland
Associated with cutaneous hemangiomas
Like cutaneous hemangiomas, tends to spontaneously involute.
Imaging: Highly enhancing, High T2 signal
Multiple parotid gland masses diff
Acinic cell carcinoma
Lymphoepithelial lesion of HIV
Mucoepidermoid carcinoma statistics
30% of salivary gland malignancy overall, of which 60% are in parotid.
No specific imaging characteristics
Adenoid cystic carcinoma
Notorious for perineural spread (in ~50-60%)
Frequently recurs post resection
Relentless but slow growth. Survival measured in decades
Acinic cell carcinoma
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
Occurs due to gnashing of teeth
Bilateral enlarged mastication muscles.
Either idiopathic or due to malocclusion, or excessive chewing.
polyostotic fibrous dysplasia.
It can affect the mandible unilaterally.
Usually seen 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
Beckwith - Wiedeman disease
Chronic facial/jaw pain
9:1 women to men.
Often precipitated by traumatic event
Anterior meniscus dislocation is most frequent (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 factoids
Very uncommon, there are few tissue types here.
Lymph nodes can have inflamation or mets
Rarely minor salivary glands can occur and can have any salivary gland tumors
Riedel thyroidits vs 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 onthe adjacent tissues
70% are solitary
Can be autonomous, in which case they suppress the remaining thyroid
Malignant thyroid cancers
Make up only 4-6% of biopsied nodules
More common in men, and as a solitary nodule
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
In pediatric cases less than 4 yrs old it is 5x as common as everything else combined.
Also women more than men
Very variable appearance.
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
Medullary carcinoma thyroid
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 detected on serum tests
Look for stippled calcifications in the mass
Anaplastic carcinoma thyroid
Highly aggressive, large and bulky on presentation
Population is older on average compared to papillary cancer.
Can be thallium or gallium avid, but not iodine.
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
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%.
Neck cystic masses
Branchial cleft cysts
Thryglossic duc cyst
Thyroid and thymic cysts
Branchial arch I
Mandible, Malleus, Incus, Tensor rympani, Masticator, Anterior digastric, Meddle ear, Tonsils
Treacher collins syndrome, abnormalitis of the external ear, hypoplastic mandible
Branchial arch 2
Nerve: CN VII
Menubrium of malleus, long process of incus, posterior digastric, inferior facial canal, tonsils, parathyroid
Persistent stapedial artery
Branchial arch 3
Nerve: 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 pharyngeal constrictor
Diseases: Aberant right subclavian
Branchial arch 5
Nerves: CN X recurrent laryngeal branch
Precursor of pulmonary arteries.
Bones/muscles: Precursor of the cricoid, arytenoids, trachea and intrinsic muscles
Calcifications in intervertebral disks
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
Juxta-articular cyst factoids
Associated with DJD
Most are synovial cysts, some are ganglion cysts
Associated with spondylolisthesis
Ossification of the posterior longitudinal ligament
Is an inflammatory degenerative condition
Associated with degenerative disease of cervical spine
Can result in compression of cervical cord with myelopathic symptoms
AKA Forestier disease
Ossification along the anterior and lateral aspect of the spine with hyperostosis of ligament insertion and ligament 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.
Inflammatory disease involving the SI joints and spine enthesopathy
Key word is Bamboo spine.
Erosion of the end plates and enthesopathy results in squaring of vertebral bodies.
Another buzz word is "shiny corner" on the plain films.
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 sleeves along the spinal column, most often in the lumbar/sacral region.
Results in scalloping of the posterior vertebral bodies, spinal canal dilation, widening of interpedicular distance and neural foramina.
There is thinning of the cortex.
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
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 nerve root thickening
CHronic inflammatory demyslinating polyradiculopathy
Hypertrophic interstitial polyneuritis
When acute onset, pain is always present
Not always so in chronic cases
Most frequent causes are Staph then Strep, peprostreptococcus, E. coli and proteus
Occurs in dialysis patients
Usually cervical spine affected first.
Aggressive appearance similar to infection with destruction 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
fungal (blasto, 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
Spinal Epidural abscess
Occurs from direct extension or hemorrhagic spread
gm negative rods,
Associated with blunt spinal trauma with hematoma
Differential includes subdural empyema.
Spinal cord sarcoid
Spinal cord is involved in 6-8% of neurosarcoid cases
There are nodules on the surface of the cord and possibly on nerve roots (similar appearance to tumor nodules).
There may be cord enlargement.
If intramedullary, can be diffuse or mass-like
MR demonstrates 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.
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 be 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 inciting event
Symptoms include back pain, leg 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
Three types of central syrinx in the spinal cord.
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 tumor is resected.
Cyst occuring within the tumor is a tumoral cyst. This is common with astrocytoma. It enhances peripherally.
Astrocytoma of the cord factoids
make up 40% of spinal cord tumors overall
Tumor is hyper-cellular, large, takes up full diameter of the cord, has no obvious margin and is often eccentric in the cord.
In children the lesion is WHO Gr I 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
Mets usually to retroperitoneal nodes
Ependymoma outside the CNS can occur in the broad ligaments and sacrococcygeal.
Myxopapillary ependymoma factoids
Makes up 13% of the cord ependymomas overall
Arising in filum with extension into the conus
Hemangioblastoma of the cord factoids
Vascular lesion usually in cervical or thoracic cord.
Not very frequent
Causes diffuse widening of the spinal cord
1/3 is associated with vHL, in which case often multiple. Otherwise usually solitary.
Ganglioma of spinal cord
A rare tumor.
Most frequently seen in children and young adults, median 12 years
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
Treated by resection
Spinal Intradural mets
Symptoms are nonspecific (headache, back pain and/or focal neural)
Usually spreads by ingrowth via virchow robin spaces.
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
aka HMSN1 (hereditary motor and sensory neuropathy), autosomal dominant
Slowly progressive distal atrophy (commonly peroneal 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 causes
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 causes
Pantopaque (not used anymore)
Lesions commonly metastasizing to the spine
Ewing sarcoma (likes sacrum and lumbar)
Pelvic lesions metastasize through Batson's epidural venous plexus.
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
Thin intravertebral vacuum phenomenon
Ct malignant fracture features
Destruction of anterolateral or posterior cortex of vertebral bodies
Destruction of cancelous bone
Destruction of pedicle
Focal paraspinal soft tissue mass
Neural crest origin tumors
Accur in infancy.
Arise from sympathetic plexus
<5 years, neuroblastoma
5-8 years Ganglioneuroma
Calcification seen in 30% and sometimes hemorrhage
Location is usually paravertebral, usually at thoracic level
The tumor extends through neural foramen to compress the neural sac
Osteoblasoma vs osteoid osteoma
The differential factor is size. A lesion over 1.5 cm diameter is an osteoblastoma. If less than 1.5 cm its an osteoid 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
When 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
Patient usually 40s to 50s and mostly male.
There is insidious onset of symptoms
Associated with subacute necrotizing myelopathy
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 with spinal artery aneurysm.
Symptoms are acute from hemorrhage, including progressive myelopahty.
This malformation is less common than SDAF
Spinal cord AV fistula
Lesion is intradural extramedullary and there are no intervening capillaries
The vessels are on the pial surface
Lesions can be ventral or lateral and can involve 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 roots are absent on the affected side
The cord is displaced to the contralateral side
A pseudomeningocele may form, and may not communicate 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 C2
Both pedicales are fractured 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 smooth and separated by a lucent zone (fibrocartilage?)
Slight association with
Morquio syndrome and
The ossicle is embedded in the transverse atlantoaxial ligment and can cause cord compression
Burst fracture types
A- comminution of both endplates. makes up 40% of burst fractures. Results from axial loading
B - fracture of superior endplate 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 from axial load in lateral bend
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 differential
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
Carotid Glomus tumor
Arises from the carotid bulb
Splays the internal and external carotids
Can grow though skull base to involve the carotid space
Can infiltrate the lumen of the jugular vein
Check serum metanephrine before trying angio
Derives from the nodose ganglion
Therefore pushes the carotid anteriorly
Can invovle CN IX through XII and cause Horner syndrome
Congenital lesions of the thyroid
1/3 are total agenesis
20% of ectopic thyroid are the only thyroid tissue and there is 3-5% CA risk
1/3 are ectopic between the tongue and the normal location
Abduscens nerve factoids
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.
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
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
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
Compresses brain stem too
Possible ipsilateral face weakness and decreased corneal reflex
Neuroblstoma brain mets imaging
Can be solid or cystic.
Can enhance, hemorrhage and calcify
Can involve leptomeninges
Spinal meningioma factoids
25% of spinal tumors overall
May coexist with neurofibromas in NF2
Carotid artery dissection predisposing factors
Ehlers-Danlos and Marfan's
Brain Capillary Telangeactasia definition
Capillary malformation with normal surrounding brain tissue
Ocular melanoma factoids
Rare in children
Rare in black population, but when occur are larger, more pigmented, more necrotic than general.
Ocular melanoma predisposition
Ocular melanoma imaging
T1 hyper/t2 hypointense
due to melanin
Signal strength related to melanin content
Amelanotic melanomas are T1 hypo/T2 hyper
CT high density
MR considered better modality
Carotid artery dissection imaging
Often is a mural hematoma, so no flap is seen and no contrast in the false lumen
Use Fat Sat to highlight methemoglobin
Often overlooked cause of anterior circulation infarction
Brain Capillary Telangeactasia imaging
Occult on angio because of small vessel size
No Ca, gliosis or hemorrhage
Does not show on T1, T2 FLAIR
Image with MR using contrast and susceptibility sequences
Uveal melanoma characteristics
Collar button configuration that interrupts Bruch's membrane
In any portion (iris, ciliary, choroid, body)
Uveal melanoma imaging
Variable MRI depending on melanin content
Hypoechoic on US
Uveal melanoma treatment
>10 mm size=enucleation
3-10 mm radiation and brachytherapy
<3mm may be benign, so biopsy and monitor
POEMS syndrome stands for
Endocrinopathy or Edema
Skin abnormalities (hyperpigmentation)
aka Crow-Fukase, Takatsuki disease or PEP syndrome
POEMS syndrome path
Combination plasma-cell proliferative disorder, polyneuropathy with effects on most body systems
Pineal cyst symptomatology
Symptoms from mass effect on aqueduct from compression
Hemorrhage can result in rapid expansion=pineal apoplexy
Pineal cyst differential
Germ cell tumor including germinoma
Warthin tumor characteristics
Arises from incorporated lymphoid tissue in parotid gland
Most are in parotid tail
Malignant transformation in 1%
Recurrence if incompletely resected
20% multicentric which can be unilateral, bilateral synchronous or metachronous
5-20% in upper neck or periparotid
Warthin tumor associations
Smoking (90% of tumors are in smokers)
Multiple lesions or bilateral suggest Epstein-Barr virus
Warthin tumor imaging
Sharply demarcated round/ovoid mass with profound intraparenchymal inhomogeneity
Most in parotid tail
Range about 2-4 cm at presentation
30% are cystic
Minimal enhancement in solid component
MR with contrast best for localization
T1 hypo in both solid and cystic component
T2 intermediate to hyper in both solid and cystic component
US-heterogeneous hypo to anechoic.
POEMS syndrome clinical
Polyneuropathy usually symmetrical and distal
due to demyelination and axonal damage to sensory, motor and autonomic nerves.
Commonly have myeloma, pappiledema, hepatosplenomegaly, lymphadenopathy, edema.
Endocrinopathy results in amenorrhea in women, gynecomastia, testicular atrophy and erectile disfunction in men.
Monoclonal IgG or IgA
75-80% have skin changes.
Clubbing of fingers
Pineal cyst characteristics
Well defined cyst in pineal region
Usually <1 cm
>1 cm needs follow-up as can enlarge
Pineal cyst imaging
Can have rim enhancement
If rim is thick/nodular suspect pineocytoma
PITFALL: contrast can diffuse in on late imaging
Proteinaceous fluid characteristics on MR=variable
Subependymal giant cell tumor characteristics
WHO grade I
Occurs in 15% of TS cases
Seeding is rare
Present when large enough to impinge on foramen of Monro with obstructive hydrocephalus
Subependymal giant cell tumor imaging
T1 iso to gray matter
T2/FLAIR hyper to gray matter
Calcifications with susceptibility on MR but hyperdense on CT
Can not be reliably differentiated from a subependymal nodule
Basilar invagination congenital causes
Also associated with syringohydromyelia, atlas occipitalization,
Basilar invagination definition
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.
Called Basilar Impression when acquired
Calcifications and cysts common
Hemorrhage is not
Prefers frontal cortex.
Rare in ventricles and cerebellum. Even more so in brain stem and spinal cord
Basilar invagination symptoms
Upper cervical cord compression syndrome (labile BP, Arrhythmias)
Posterior skull pain
Myxopappilary ependymoma characteristics
Slow-growing tumor arising from the ependymal cells of the filum terminale.
13% of all spinal ependymomas
Does drop mets, but not as often as others
Myxopappilary ependymoma symptoms
occasionally bowel and bladder dysfunction
Myxopappilary ependymoma imaging
Heterogeneous due to hemorrhage calcs and cysts
Typically spans 2-4 vertebral bodies
T1 hypo/T2 hyper, again heterogeneous
Myxopappilary ependymoma location
Occurs almost exclusively in conus medullaris, filum terminale, and cauda equina.
CN V1 branch
Ophthalmic, runs inferiorly in cavernous sinus, enters in superior fissure. Supplies upper face, lacrimal gland, eye, nose.
CN V2 branch
Goes through foramen rotundum, runs in pterygopalatine fossa. Supplies maxillofacial region. Maxillary nerve branch goes into inferior fissure.
CN V3 branch
Supplies mastication muscles motor, lower face, ear sensory, TMJ, tympanic membrane.
Trifurcates to auriculotemporal, lingual and inferior alveolar nerves.
Hypoglossal canal diseases
Large glomus jugulare
Neurotropic spread of tumor
Adjacent osteolysis or hyperostosis
Obtuse angle with dura
Calcification about 20%
Alanine peak on MRS
Hyperdense on CT
Ext into auditory canal are rare.
Can encase and compress adjacent vessels
Epidermoid cyst imaging
Well defined bony lesion with sclerotic margins
Low density, but not fat
Expand to fill available spaces
T1 hypo, T2 hyper like water, but bright on FLAIR
Usually very diffusion restricting on DWI.
Typically do not enhance, but may have a bit of wall enhancement.
Mostly large, over 4 cm,
Hyperdense on CT,
Hyperostosis or calcification is rare.
Subarachnoid seeding locations by frequency
Cerebellopontine cistern along CNs
Epidermoid cyst location
Typically cerebellopontine cistern causing trigeminal neuralgia and facial paralysis.
Extradural much less common than intradural in which case
Choroid plexus papilloma presentation
Hydrocephalus and papilladema due to CSF overproduction or obstruction.
Choroid plexus papilloma imaging
Can extend all the way to foramen of Luschka
Low T1, mixed T2.
CNS lipoma associations
Agenesis of corpus callosum.
60% association with a congenital anomaly of neural elements
Juvenile pilocytic astrocytoma imaging
Hypo T1, Hyper T2/FLAIR
Cystic portion follows CSF characteristics.
Solid portion enhances strongly
Epidermoid CNS cyst definition
Arise from rest of epidermoid tissue resulting in collection of keratin, cholesterol epithelium debris (white cheesy stuff)
Homogeneous hyperdense (as compared to ependymoma)
Hypo T1, iso T2
Not much edema
Can seed (sugarcoating) up to 50%
Low NAA:Cho ratio. Usually not lactate
Juvenile pilocytic astrocytoma locations
60% in posterior fossa
Also likes optic pathways and hypothalamus.
Rhabdoid tumor characteristics
Often hemorrhagic, necrotic, calcifications and cystic change.
About 1/3 have subarachnoid dissemination at presentation.
Can have cystic change
Displaces 4th ventricle inferiorly
High seeding rate
Usually midline from vermis then growing upwards in kids.
More often lateral in cerebellum in older patients.
Rhabdoid tumor locations
About half in posterior fossa
Multifocal or spinal is rare.
Prognosis varies by site
Filum terminale best (WHO I)
Posterior fossa worst (WHO II)
About half calcify (typically punctate)
Can have hemorrhage.
Hypo to isodense
CLASSIC: Calcified mass in 4th ventricle extending through Luschka and Magendie.
T1 hypo-/T2 intermediate
Hypointensity may reflect calcification
Usually 4th ventricle when in posterior fossa. (can hang out of foramina)
About 20% intraparenchymal
CNS hemangioblastoma clinical
Commonly present with headache, ataxia, nausea, vomiting, vertigo.
Often has polycythemia due to increased erythropoietin
CNS hemangioblastoma imaging
Typically cystic mass with solid mural nodule (60%)
Highly vascular-serpentine signal voids
Can be solid or purely cystic. Solid ones enhance avidly.
CNS mets imaging
Most are low density excepting calcifications, hemorrhage, proteinacious material
Variable appearance of T1 and T2
Pleomorphic xanthoastrocytoma locations
Preference for peripheral temporal lobes
Meningeal base in 2/3 cases
Cerebral neuroblastoma characteristics
Often cystic 1/2 to 2/3, hemorrhagic, pediatric
High recurrence and seeding rate
Usually large at diagnosis
Pleomorphic xanthoastrocytoma imaging
Cysts in 1/3 to 1/2
Hemorrhage and calcification uncommon.
Cerebral neuroblastoma imaging
Heterogeneous and heterogeneously enhancing on CT and MRI
Not much edema
Supratentorial as opposed to ependymoma
Arise in periventricular neuroepithelium, so usually appose ventricles.
Large at diagnosis with enhancement, edema, peripheral necrosis, cysts.
Fairly well circumscribed.
T1 iso, T2 iso, FLAIR hyperintense, basis for identification
Desmoplastic Infantile Ganglioma imaging
Cysts are the rule with
Peripheral rim or nodular enhancement.
May have calcified rim
T2 hypointense rim due to desmoplasia
Often cystic (more in younger pts), hypodense
MRI features vary depending on cyst composition
Cerebral cortex or cerebellum (what's left)
Can be called Lhermite-Duclos if cerebellar
Very bright T2
Septations in triangular pattern
Enhancing (about 1/3)
Usually no edema
Very slow grower.
Peripherally, cortex and subcortical WM almost always involved.
Anaplastic astrocytoma imaging
Ill defined borders
prolific vasogenic edema
Likely to enhance.
If there is necrosis, bump to GBM status.
Circumscribed (WHO I)
pilocytic giant cell
Diffuse (WHO II) least likely to enhance.
gemistocytic exclusively in cerebral hemispheres.
(80% convert to GBM)
Anaplastic (WHO III)
GBM (WHO IV)
Characterized by necrosis in the tumor.
High choline levels on MRS, the higher, the worse.
Subependymal giant cell astrocytoma imaging
Projects into the ventricle
Enhance (tubers do not)
A lot of subependymal things enhance that do not on CT, so CT may be better to look for this lesion.
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
Gliomatosis cerebri imaging
Subtle. Maybe loss of G/W junction little mass effect
Better, but still subtle.
Diffuse subtle T2 hyperintensity
Minimal enhancing if at all
Many appearances, mass, coating, malignant effusion
Thallium 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
Engulfed pineal gland (Ca++ inside pineal inside tumor)
Iso T1, Slightly hypo T2
MRI: Intermediate on T2
Classic: Exploded pineal calcification
CNS PAN imaging Rads
Nonspecific hyper T2 white matter lesions
Retinocochleocerebral vasculopathy imaging
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
Post SAH morbidity
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
Capillary telangiectasia association
Cerebral lesions can occur in association to Osler Weber Rendu (aka hereditary hemorrhagic telangiectasia)
Reasons to do MRA to screen for aneurysm
Worst headache, 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.
Cavernous angioma imaging
Appears as a high density lesion on CT
Can calcify and enhance
Shows blood products of various ages.
! Complete rim of hemosiderin
No feeding arteries.
Can have an early vein or blush
DAI most likely locations
Body and splenium of corpus callosum
Superior cerebellar peduncle
Brain death imaging
Negative Technetium-HMPAO scan
Transtentorial and 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)
Epidural abscess imaging
Epidural low density mass
T1 hypo or iso
Subdural empyema imaging
Possible hyperintensity of underlying brain.
Restrict diffusion. (hygromas do not)
Imaging is usually normal, especially if already treated.
Distended subarachnoid space.
FLAIR hyperintensity of subarachnoid fluid.
Acute general cerebral swelling.
Enhancing leptomeninges (not prognostic, and more common with bacterial infection)
Carcinomatous meningitis pachymeningeal or leptomeningeal
Tends to be pachymeningeal - follows contour of calvarium (dura)
Bacterial meningitis pachymeningeal or leptomeningeal
Tends to be leptomeningeal - follows contour of brain (pia, arachnoid)
Subdural empyema causes
Paranasal sinusitis (older children, adults)
Purulent bacterial meningitis (infants)
Osteomyelitis of calvarium
Otitis media, mastoiditis
Idiopathic hypertrophic cranial pachymeningitis imaging
Dural thickening like pseudotumor
T2 hypo, without involving brain.
Idiopathic hypertrophic cranial pachymeningitis factoids
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.
Related to pseudotumor, Tolosa-hunt, other fibrotic diseases.
Cerebral abscess imaging
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.
Cchoroid plexitis factoids
Rare since there is a BBB there.
Most often not seen alone, but in conjunction with other infection; encephalitis, meningitis.
Pachymeningeal enhancement diferential
Idiopathic hypertrophic cranial
Inflammatory disease (sarcoid)
Mets, including skull
CNS simplex herpes in neonates
Type 2 responsible for neonatal infections (direct transfer during birth and also part of TORCH with all the problems thereof)
Hyperdensity of gray matter
Intracranial calcifications 17-21 days after infection
Low density, high intensity parenchymal abnormalities-gyriform enhancement
CNS simplex herpes in adult
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
Cerebral abscess capsule progression
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.
CNS herpes zoster imaging
High T2/FLAIR and low density on CT
Gyriform enhancement in segmental distribution.
Postvaricella encephalitis locations
CNS simplex herpes in adult
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.
Postvaricella encephalitis symptoms
Headache, N/V, fever, nuchal rigidity, cerebellar ataxia, parkinsonism 1-3 weeks after chickenpox.
Subacute sclerosisng panencephalitis progression
Intellectual deterioration, ataxia, chorea, dystonic rigidity, SZ,
myoclonus, vision deterioration including cortical blindness
Unresponsiveness, autonomic dysfunction
Subacute sclerosisng panencephalitis imaging
Hyper T2/FLAIR lesions
Basal ganglia particularly putamen
Enhancing with mass effect early in course
Predictable T2/FLAIR hyperintense lesions
Can have enhancement of U fibers (worse symtpoms)
Japanese encephalitis imaging
Bilateral T2/FLAIR in thalami and putamina.
Thalamic lesions prone to hemorrhage
Usually does not enhance.
AIDS dementia complex imaging
High T2/FLAIR in WM, basal ganglia, caudate nuclei without enhancement
Diffuse pallor of centrum semiovale
Cryptococcosis imaging findings
Dilated Virchow-Robin spaces in young pt.
Multiple milliary enhancing parenchymal leptomeningeal nodules including choroid plexus, trigone, spinal cord and nerve roots.
CNS coccidiomycosis imaging
Dilated V-R spaces like crypto
Focal infarctions due to vasculitis.
Hyper PDW/FLAIR in cisterns
Thick basilar meningitis
Meningeal and parenchymal granulomas
CNS mucormycosis imaging
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
CNS aspergilosis imaging
May or may not have complete enhancing capsule (distinction from nocardia).
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 aggressive clinical features.
CNS TB imaging
Uniform dense enhancement of basal cisterns
Variable on MRI
May adhere to dura giving false appearance of meningioma
Exudative meningitis most often involves basal cisterns.
Involvement of perforating vessels may cause basal ganglia infarcts (vertical rising up from basal cistern along perforator territory)
Hydrocephalus by obstruction
various enhancing nodules
calcified granulomas (and raw ones too)
multiple T2/FLAIR hyper lesions with vasogenic edema and ring or nodular enhancement on T1.
CT areas of low density with little or no enhancement, gyriform enhancement, or isodense enhancing nodules.
CNS mucormycosis clinical
Bloody nasal discharge
Dark swolen turbinates
Cranial nerve palsy
Progresses rapidly to stroke, encephalitis, death
CNS cysticercosis locations
Can be found in
parenchyma (cortical and deep gray matter)
subarachnoid space (suprasellar, cerebellopontine angle cistern)
spine is rare ( only 3%) can cause spinal cord compression
CNS cysticercosis imaging
calcification in parenchyma, classic off center
spherical 1-2 mm diameter scolex surrounded bu 7-12 mm fully calcified sphere., which only occers in dead larvae
Typically the parenchymal cysts are small (1cm) whereas the subarachnoid ones can be much bigger (up to 9cm): differential therefore being arachnoid cyst.
CT better than MR (hypointense T2 nodule)
Sarcoidosis CNS imaging
T2/FLAIR hyper parenchyma and G/W junction
Diffuse gyriform enhancement
nodules may calcify
can cavitate, but not as frequently as TB
CNS paragonimiasis imaging
exudative aseptic inflammation
infarction on one side of brain
granulomatous lesion around the worm
Multiple conglomerated, interconnected granulomas around a focus, which the calcify in chronic stage giving "soap bubble calcifications"
CNS Behcet's imaging
multiple high intensity lesions
CLASSIC - mesodiencephalic junction lesion with edema extending along tracts in brain stem and diencephalon.
CNS Behcet's locations
Classic mesodiencephalic junction lesion with edema extending along tracts in brain stem and diencephalon.
optic nerve (rare)
CNS cysticercosis stages
Vesicular: viable parasite with intact membrane and therefore no host reaction. Clear fluid.
Colloidal vesicular: parasite dies within 4-5 years untreated, or earlier with treatment and the cyst fluid becomes turbid. As the membrane becomes leaky edema surrounds the cyst. This is the most symptomatic stage.
Granular nodular: edema decreases as the cyst retracts further; enhancement persists.
Nodular calcified: end-stage quiescent calcified cyst remnant; no edema.
The evolution can take average 5 years (2-10)
CNS Behcet's differential
Other vasculitides (primary arteritis)
Inflammatory diseases (sarcoid)
CNS sarcoidosis differential
Meningioma (especially if extra-axial)
CNS sarcoidosis ophthalmic involvement
25% have ophthalmic manifestations
lacrimal gland involvement
optic nerve/sheath involvement
Dramatic response to steroid
Whipple disease clinical
Classic: man 40-50 with myoclonus, ophthalmoplegia, progressive dementia, steatorrhea, malabsorption, arthritis!! high suspicion of Whipple
Rasmussen encephalitis clinical
Focal motor seizures followed by
progressive loss of ipsilateral motor function
neuronal loss without inflammation late in disease
Rasmussen encephalitis imaging
large regions of diminished cerebral perfusion
Crossed cerebellar diaschisis (diminished perfusion in contralateral to the affected area)
Decreased NAA, elevated Cho, Glutamate (nonspecific of course)
Acute necrotising encephalopathy of childhood imaging
multifocal symmetrical lesions with thalami affected in all cases, internal capsules in most.
Acute necrotising encephalopathy of childhood locations
Thalami affected in all cases, internal capsules in most.
Adrenoleukodystrophy MRS findings
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)
Brain abscess phases on MR
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.
Acute necrotising encephalopathy of childhood clinical
Elevated liver enzymes, lactate dehydrogenase, ammonia
Elevated CSF pressure
Elevated CSF protein, myelin basic protein
Multiple sclerosis imaging
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).
Magnetization transfer is a new technique that can bring out more lesions.
Multiple sclerosis differential
Lyme, Vasculitides (primary angiitis, PAN, Behcet's, Syphilis, Wegener's, Sjogren, SLE), Hypertensive ischemic lesions, Virchow robin spaces, Migraine, Trauma, UBO's
Multiple sclerosis diagnosis criteria
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
Brain abscess phases on CT
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.
A secondary demyelinating disease of vascular etiology.
Characterized by recurrent TIAs, strokes, dementia, depression, pseudobulbar palsy, hemi- or quadriplegia.
Affects frontal lobes, temporal lobes, insula.
Deteriorate with subcortical dementia, incontinence, pseudobulbar palsy
Cerebral amyloid angiopathy differential
Multiple cavernous malformations
Previous traumatic injury
Cerebral amyloid angiopathy associations
Late post radiation nectrolsis
again, NOT associated with systemic amyloidosis
ADEM imaging characteristics
Lesions may be multiple 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.
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.
Starting around 40 or 50, usually resulting in stroke and death within 20 years.
Progressive multifocal leukoencephalopathy
Focal regions of low T1 with high T2, most often nonenhancing.
Post anoxic encephalopathy imaging
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
Central pontine myelinolysis locations
May involve extrapontine structures actually, including thalamus, putamen, caudate, all capsules, claustrum, amygdala, cerebellum
Often can see normal intensity descending corticospinal tracts outlined by the white matter hyperintensity.
No mass effect or enhancement.
Disseminated necrotising leukoencephalopathy imaging
CT: Marked low density white matter
Predilection for periventricular white matter and centrum semiovale, sparing U fibers.
MR: diffuse high T2 throughout white matter, possibly enhancing.
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.
Can progress from anterior to posterior or reverse. The advancing edge represents zone of dysmyelination with enhancement. Nonenhancing regions are gliotic.
Impaired hearing and vision, abnormal skin pigmentation, hypotonia, difficulty swallowing, behavioral, seizures.
Vanishing white matter disease clinical
Clinical: Prominent ataxia, spasticity, optic atrophy, relatively preserved mental capabilities.
Chronic progressive course with decline associated with episodes of minor infections and head trauma.
Vanishing white matter disease imaging
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.
External hydrocephalus imaging
CT/MR: Dilation of the CSF spaces over frontal lobes along the interhemispheric fissure, but relatively normal sized ventricles.
External hydrocephalus demographics
typically presents at less than 2 years old with rapidly enlarging head circumference.
Usually resolves by age 3-4 and head circumference returns to normal.
Shunt failure imaging
Compare the ventricular size with priors.
Stress to temporal horn and third ventricle, these dilated first.
Contrast normally clears from shunt tube in 3-10 minutes and children, 10-15 minutes in adults.
Evaluate reflux of contrast into ventricles on prior and should not have" spread.
Look for spillage of contrast into the peritoneum, which is what should happen.
Pseudotumor cerebri clinical.
Frequent headaches particularly on waking up. Cranial nerve palsies. Papilledema or visual field deficits.
Pseudotumor cerebri associations.
Intracranial venoocclusive disease .
Pseudotumor cerebri imaging
ventricles are either normal or slightly small.
Cerebral subarachnoid space is slightly enlarged.
Most MR studies are normal, although there can be subtle increased white matter T2 hyperintensity.
Venous sinuses and veins may be small and may enlarged after lumbar puncture.
Optic nerve sheath complex is enlarged.
There is reverse cupping of the optic nerve corresponding to degree of visual loss.
Pseudotumor cerebri demographics
Typical patient is an obese (95%), block (62%), young to middle-aged female.
Progressive supranuclear palsy imaging
Dilation of the third ventricle.
Atrophy of the midbrain.
Possible decreased substantia nigra.
T2 hyperintensity of periaqueductal gray.
Increased iron in the putamina
Cortical-basal ganglionic degeneration imaging
Asymmetric thickening of pre-and postcentral gyri.
Central sulcus dilation.
Atrophy of paracentral structures.
Superior parietal lobule.
Knife blade atrophy particularly of the superior parietal lobule and superior frontal gyrus.
central sulcus asymmetry is characteristic.
Temporal and occipital lobes are less involved.
Possible subcortical gliosis with corresponding T2 signal.
Cerebrotendinous xanthomatosis imaging
Gray matter (globus pallidus), supratentorial white matter (corticospinal tracts especially in cerebral peduncles) in demonstrate focal T2 high signal.
Dentate nucleus microcalcifications may be visible on CT.
Possible enlargement of V-R. spaces
in the spine there is selective defect on posterior and lateral columns.
Cerebellar involvement may extend throughout the white matter from the dentate nucleus.
Cerebrotendinous xanthomatosis clinical
Typical patient: Young. presenting cataracts with symmetric the gray matter and posterior column lesions on imaging.
Cerebellar atrophy presentation
Clinical presentation of olivopontocerebellar degeneration
Truncal and limb ataxia, problems with speech, mild mental impairment.
Olivopontocerebellar degeneration imaging findings
Pons, inferior olives, and cerebellar peduncles are strikingly small.
There is marked cerebellar atrophy, particularly the vermis.
Clinical presentation of aerated. Cerebellar atrophy
Lower extremity gait ataxia.
Ophthalmoparesis in later life.
Slow but relentless progression.
Vermian/holocerebellar atrophy and white matter hyperintensity.
Possible occult intracranial cardiovascular malformations = dark dot in gradient echo sequence to to hemosiderin.
multiple areas of cortical high signal on T2, often crossing traditional cerebral artery distribution.
May be hyperintense on DWI, but ADC is not low-therefore not restricting.
lesions result in time with minimal residual sulcal dilation.
Lesions can also occur in that the payments, caudate nuclei, thalami and may or may not enhance.
3-hydroxy-3-methylglutaryl-coenzyme A lyase deficiency clinical presentation
Mental status changes.
Leukodystrophy with preferential involvement of deeper arcuate fibers on MR.
Glutaric acidemia imaging
Subarachnoid space dilation anterior to the temporal lobes.
Basal ganglia volume loss.
homocystine area clinical presentation.
Multiple thrombotic events, which are arterial and venous, including strokes.
Length of subluxations (up and inward)
May also have osteoporosis, cataracts, scoliosis and biconcave vertebral bodies.
Maple syrup urine disease imaging
Ultrasound: Symmetric echogenicity of periventricular white matter, basal ganglia (mainly globus pallidus) and thalami.
CT and MR: Diffuse edema in similar locations, cerebellum and capsules. Delayed myelination.
MRS: Branched chain aminoacid peak at 0.9 ppm.
Clinical presentation of propionic acidemia
all detected within the first month.
Propionic acidemia imaging
Abnormal white matter hyperintensity.
Basal ganglia lesions (globus pallidus in methylmalonic acidemia, putamina in propionic acidemia)
MRS: lactate peak.
White matter demyelination posteriorly often including the optic radiations.
Neural migration abnormalities.
Cerebellar and brainstem high signal foci.
Basal ganglia calcifications.
Glutaric acidemia II imaging
Globus pallidus and white matter T2 hyperintensities.
Hyperdense basal ganglia on CT.
Batwing dilation of sylvian fissures.
Temporal arachnoid cysts.
Arachnoid cyst location if infratentorial
Cerebellopontine angle cistern.
Quadrigeminal plate cistern.
Rathke cleft cyst imaging
MR: Well-defined mass with variable T1 and T2 hyperintensity depending on protein content.
no calcification or enhancement.
CT: CSF density protrusion through a bony defect in calvarium.
MR: Continuity of meningocele with underlying leptomeningitis.
Fetal alcohol syndrome
Trisomy 13. 15. 18
CT: Absent or only partially formed falx, interhemispheric fissure, lateral ventricles. Corpus typically gone, 3rd ventricle abnormal. Olfactory bulbs may also be absent.
This is the one lesion where posterior portions of corpus callosum may be formed, but anterior portions are absent. (except the rostrum, which forms after the splenium)
Focal cortical dysplasia (polymicrogyria),
gray matter heterotopias
Agenesis of septum pellucidum (80-90%)
Agenesis of Corpus Callosum midline abnormalitly associations
interhemispheric arachnoid cyst,
incomplete formation of hippocampal region,
absent cingulate sulcus.
Agenesis of Corpus Callosum congenital associations
Chiari I and II,
fetal alcohol syndrome,
Order or corpus callosum development
From genu posteriorly to splenium and then rostrum. Therefore if splenium is gone, so is the rostrum despite being on opposite sides.
CNS hamartoma locations
In CNS affinity for the hypothalamic region followed by cerebral cortex-subcortical region, even periventricular.
CNS hamartoma clinical
Presents with precocious puberty, occasionally visual disturbances.
Boys > girls.
Seizures common , often gelastic seizures.
CNS heterotopia clinical
Usually pt has seizures, weakness, spasticity, hyperreflexia, developmental delay.
Nodular types CNS heterotopia
Subependymal and subcortical variants.
Possibly x linked.
If subcortical, may have abnormal sulcation.
Affected hemisphere may be atrophic
Band type CNS heterotopia
Associated with severe developmental delay and earlier onset of seizures than nodular.
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.
White matter thickness is normal (as opposed to hemimegalencephaly which has increased white matter or pachygyria, which has decreased white matter).
Can not distinguish pachygyria from polymicrogyria on MR because the microgyri run together. (maybe on stronger magnets?)
Congenital bilateral perisylvian syndrome presentation
Presents with seizures, pseudobulbar paresis, developmental delay.
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.
Seizures, hemiplegia, developmental delay, abnormal skull. The enlarged side may have been small in infancy.
Megalencephaly associated syndromes
Usually presents due to skull base foraminal stenosis-cranial nerve palsies, optic atrophy, stenosis of jugular and carotid foramina.
Congenital toxoplasmosis clinical
Usually fetal death, but if survives, developmental delay, seizures.
Congenital CMV clinical
Clinical: Hearing loss, Psychomotor retardation, visual defects, seizures, optic atrophy
Congenital HIV clinical
Asymptomatic at birth, eventually developmental delay, late spastic paraparesis, ataxia
Partial asphyxia in premies grading
1) evanescent periventricular 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 premies US progression
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.
Germinal matrix hemorrhage grading
1) Limited to germinal matrix
2) Germinal matric and intraventricular
3) Germinal matric and intraventricular with hydrocephalus.
4) Germinal matrix, intraventricular and intraparenchymal
Germinal matrix hemorrhage imaging
Hydrocephalus secondary to clot, plugging up aqueduct of arachnoid villi occurs in 70%.
Mesial temporal sclerosis imaging
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.
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 pilocytic astrocytoma), which are slow growing and do not require treatment until symptomatic.
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) axillary/inguinal freckling 5) 1 or more bone dysplasias or psudoarthrosis of a long bone 6) optic nerve glioma 7) diagnosed first degree relative.
Plexiform neurofibroma locations
Tend to involve scalp, neck, mediastinum, retroperitoneum, cranial nerve V and orbit.
Clinical diagnosis: 1 of the following
1) bilateral vestibular acoustic schwannomas,
2) diagnosed 1st degree relative
a single acoustic schwannoma or 2 of (schwannoma, neurofibroma, meningioma, glioma) elsewhere.
Can also often see posterior lenticular capsular cataract.
Enhancing masses in and around the cerebellopontine angle or extending into the internal auditory canal. Generally slightly hyperintense on T2.
Tuberous sclerosis characteristics
Adenoma sebaceum (up to 90%),
mental 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%),
angiomyolypomas of kidney (up to 90%),
cystic skeletal lesions.
Intracranially: periventricular subependymal nodules, cortical and subcortical peripheral tubers, white matter hamartomas, subependymal giant cell astrocytomas.
Tuberous sclerosis imaging
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.
Tuberous sclerosis tuber locations
Cortical tubers most frequent 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.
Neurocutaneous melanosis malignant transformation
Malignant degeneration of skin lesions uncommon
About 50% transformation rate of brain lesions.
Parenchymal or intramedullary infiltration is hallmark.
Usual location is the lower thoraco-lumbar region. T8-T12 about 25%,
The rest in lumbar.
Bone abnormalities such as
wide interpediculate distance,
Hairy skin patches in 75%.
Also associated with
Filum terminale abnormalities associations
midline bony defects in lumbosacral region,
fatty infiltration of filum
Usual presentation before 3 (98%) with
signs of ocular inflammation.
calcifications in the posterior globe with extension into vitreous. Homogeneous or irregular. Up to 95 % of pts.
Absence of calcification makes retinoblastoma highly unlikely, esp in the young population.
MR: Moderately elevated T1, low T2.
Most are sporadic, but about 10% familial autosomal dominant (these more commonly bilateral and multifocal).
Familial retinoblastoma associations
High incidence of non-ocular tumors:
midline primitive neuroectodermal,
basal cell carcinoma,
Infiltrative form of retinoblastoma
Presents at mean age 6,
unilateral with retinal detachment,
thick irregular nodular leaflets,
frequent vitreous dissemination.
Calcification is rare,
confusible with Coat's disease
Persistent hyperplastic primary vitreous imaging
CT: look for the S shaped Cloquet canal
MR: variable intensity, again, look for the Cloquet canal
Usually microphthalmic, possibly small flattening of anterior chamber.
CNS Toxocara canis infection imaging
CT: diffuse hyperdensity in globe WITHOUT calcification. There may be thick enhancement of the sclera.
MR: High T1 and T2 in globe.
Serous choroidal effusions 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
Choroidal osteoma differential
Differential includes amelanotic melanoma,
leukemic or lymphomatous infiltrates,
macular choroidal scars,
resolving subretinal hemorrhage.
Retinal detachment associations
Associated with retinoblastoma,
senile macular degeneration.
Choroidal serous or hemorrhagic detachment associations
inflammatory choroidal lesions,
Posterior hyaloid space detachment associations
Posterior vitreous detachment
Globe tenting causes
Associated with acute trauma,
carotid cavernous fistula,
hemorrhage into lymphangioma and varix.
Posterior scleritis imaging
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
May be associated with:
midline craniocerebrofacial clefting including sphenoidal encephalocele,
agenesis of corpus callosum,
Is part of CHARGE syndrome,
also Len's microphthalmia,
Waardenburg anophthalmia syndrome.
Cone or notch deformity, usually in posterior globe, which may involve the optic nerve. Eversion of position of the posterior globe may be present.
posterior peripapillary staphyloma
and globe trauma
Most are sporadic
There is an autosomal dominant form. In this case colobomas are bilateral.
Optic nerve drusen imaging
On CT, punctate calcifications at the junction of nerve and globe.
MR is not good.
Often only identifieable by imaging since the optic nerve surface looks fine to the ophthalmologist
Optic nerve atrophy associations
Congenital optic nerve hypoplasia,
ischemic optic neuropathy,
Optic neuritis imaging
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 neuritis associations
Optic nerve glioma demographics
Mean age of presentation is 8.5 when overall,
(5 when associated with NF1, 12 without)
Optic nerve involvement more common in females.
Chiasmal involvement is equal.
Optic nerve glioma symptoms
Afferent pupillary defect followed by proptosis.
Optic nerve glioma imaging
Tortuous, enlarged 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 symptoms
Insidious loss of vision,
Optic nerve sheath meningioma differential
Hemangioblastoma of optic nerve in vHL,
rarely optic nerve glioma.
Optic nerve sheath meningioma 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
Calcification is not infrequent (unlike nerve sheath meningioma, which does not calcify)
Orbital hemangioma demographics
Presents in teens to 40s with slow onset proptosis, visual disturbance.
Orbital hemangioma 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.
Orbital hemangioma differential
Hemangiopericytoma on CT, neurofibroma, schwannoma, benign mesenchymal tumor.
Orbital lymphangioma 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.
Orbital lymphangioma demographics
Peak presentation at 23 years with range from newborn to decrepit.