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Lymphoma mets to brain

Brain and abdomen involvement is very rare

Differential of restricted diffusion

Infarct
Abscess
Neurotoxic chemotherapy
Radiation
Artifact

CNS complications in ALL

Chemotherapeutic agents
CNS radiation
Coagulopathy
Marrow transplantation
Immunodeficiency

Methotrexate CNS complications

Intrathecal or systemic
No specific age group
Restricted diffusion resolves with symptoms
Long term leukoencephalopathy.

NAA NMR peak

2 ppm
Active neurons
Low in neoplasms that destroy neurons and demyeliniation

Creatinine NMR peak

3 ppm

Choline NMR peak

3.2 ppm
Cellular turnover.
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.

Rubrospinal tract

Motor to contralateral limbs
Red nucl-Decussation in ventral tegmentum-Lateral funiculus-posterolateral cord white matter lateral to corticospinal tract

Reticulospinal tract

Automatic movements (strethc, walk, head coordination)
Pons-medulla-ipsilateral anterior column in cord.

Vestibulospinal tract

Balance, posture, head coordination

Medial lemniscus

Touch and limb position
Posterior WM-medulla dorsal nuclei-decussation-medial lemniscus-thalamus-anterior capsule-primary sens cortex

Spinotholamic tract

Pain and temperature
Dorsal horn-spinal decussation-anterolateral spinal tract-pons reticular formation-medulla-thalamus

Lateral lemniscus

Auditory
Auditory in caudal pons-crossed and uncrossed to inferior colliculus-medial geniculate-priomary aud cortex.

Origins of cranial nerves

1-4 from midbrain
5-8 from pons
9-12 from medulla

CN III

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

CN IV

Trochlear
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.

CN V

Nucleus medial to middle cerebellar peduncle.
Exits laterally, synapses in Meckel's cave contains Gasserian ganglion, then trifurcates.

CN VI

Abducens
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.

CN VII

Facial
Nucleus in midpons anterolateral to abducens.
Fibers circle abducens nucleus before exiting anteriorly. Crosses cerebellopontine angle cystern then into auditory canal (anterior superior).

CN VIII

Nucelui in superior medulla at base of inferior cerebellar peduncle. Cochlear division runs anterior inferior in auditory canal. Vestibular branches run posterior.

Cn IX

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.

CN X

Vagus
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.

CN XI

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.

CN XII

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
2 Linguial
4 Facial
6 Maxillary
7 Superficial temporal frontal and parietal
6 Posterior auricular
5 Occipital
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

Muscular
Occipital
Segmental spinal
Anterior spinal, supplies most of the cord.
Posterior meningeal.
First branch in intracranial compartment is the PICA

Basilar artery branches

AICA
Superior cerebellar.
Terminates as the two PCAs most of the time.

Cribriform plate

Contents: Olfactory nerves.
Diseases: Esthesioneuroblastoma

Optic canal

Contents: Optic nerve, Ophthalmic artery
Diseases: Optic nerve gliomas, meningniomas

Superior orbital fissure

Contents: Oculomotor, trochelar, abducens, V1. Ophthalmic veins, sympathetic nerve plexus, small arteries

Foramen rotundum

Contents :Maxillary (V2)
Diseases: Schwannomas, Meningiomas, PNS

Foramen ovale

Contents: Mandibular (V3), lesser petrosal nerve, small arteries, emissary veins.
Diseases: Schwannomas, Meningiomas, PNS

Stylomastoid foramen

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)

Foramen magnum

Contents: Spinal cord, vertebral arteries, spinal arteries and nerves
Diseases: Meningniomas, chordomas, schwnnomas.

Foramen spinosum

Contents: Middle meningeal artery/vein, meningeal V3 branch, lesser superficial petrosal nerve.
Diseases: ?

Foramen lacerum

Contents: Carotid artery and vidian nerve cross over it. Greater petrosal nerve.
Diseases: PNS

Incisive canal

Contents: Nasopalatine nerve, palatine arteries
Diseases: cysts

Greater palatine canal

Contents: Greater palatine nerve, palatine vessels
Diseases: PNS

Carotid canal

Contents: ICA, sympathetic plexus.
Diseases: PNS

Foramen of Vesalius

Inconstant emissary foramen anterior and medial to foramen ovale.
Contents: Emissary veins
Diseases: aneurysms

Petrosal foramen

Contents: Lesser petrosla nerve
Diseases:

Foramen cecum

Contents: Emissary vein
Diseases:

Vestibular aqueduct

Contents: Endollymphatic duct, meningeal branch of occipital artery
Diseases: Meniere's disease, congenital stenosis, patulousness

Condylar canal

Contents: Emissary vein, meningeal branch of occipital artery
Diseases:

Mastoid foramen

Contents: Emissary vein, meningeal branch of occipital artery
Diseases:

Palatovaginal canal

Contents: Pharyngeal branches of pterygopalatine ganglion and maxillary artery
Diseases: PNS

Cochlear aqueduct

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

Infraorbital foramen

Contents: Infraorbital nerve and vessels
Diseases: blow-out fractures

Mental foramen

Contents: Mental nerve and vessels
Diseases: Squamous cell carcinoma

Mandibular foramen

Contents: Inferior alveolar nerve and vessels
Diseases: Schwannomas, Squamous cell carcinoma

Pterygomacillary fissure

Contents: Maxillary artery, Maxillary nerve, sphenopalatine veins
Diseases: Juvenile andiofibromas

Vidian canal

Contents: Vidian nerve and artery
Diseases: PNS

Meningothelial origin tumors

Meningioma
Meningothelial
Fibrous
Transitional
Psammomatous
Angiomatous
Microcystic
Secretory
Metaplastic
Clear cell
Chordoid
Atypical
Papillary
Rhabdoid
Anaplastic meningioma

Mesenchimal origin tumors

Lipoma
Angiolipoma
Hibernoma
Liposarcoma
Solitary fibrous tumor
Fibrosarcoma
Malignant fibrous histiiocytoma
Leiomyoma
Leiomyosarcoma
Rhabdomyoma
Rhabdomyosarcoma
Chondroma
Chndrosarcoma
Osteoma
Osteosarcoma
Osteochondroma
Hemangioma
Epithelioid hemangioendothelioma
Hemangiopericytoma
Angiosarcoma
Kaposi Sarcoma

Melanocytic origin tumors

Diffuse melanocytosis
Melanocytoma
Malignant melanoma
Meningeal melanocytosis

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)

Schwannoma imaging

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.

Hemangiopericytoma characteristics

Meningeal mesenchymal tumor deriving from smooth muscle pericyte cells.
More agressive than most meningiomas with higher recurrence.

Meningioangiomatosis

Rare
Associated with NF II
Usually in cortex, but about 10% are meningeal
Slow process
Calcifications frequent
Proliferating vessels

May present with seizure in young pt.

Neurogenic tumors

Schwannomas
Neurofibromas
Neuromas

All look alike on imaging, path necessary for diagnosis.

Cellular schwannomas

Antoni A cells presominate
Likes CN V VI pelvis, retroperitoneum, mediastinum

Plexiform Schwanomas

Found in skin, subcutaneous soft tissues
associated with NF 2

Melanotic schwannomas

Pigmented
Younger population
Like spinal nerves over cranial.

Cerbellopontine angle masses

Vestibular schwannoma (75%)
Meningioma (10%)
Epidermoid (5%)
Facial nerve schwannoma (4%)
Aneurysm
Vert, basilar, posterior, PICA
Brain stem glioma
Arachnoid cyst
Paraganglioma
Hematogenous metastasis
Subarachnoid spread of tumor
Lipoma
Hemangioma
Choroid plexus papilloma
Ependymoma
Desmoplatic medulloblastoma

Neurofibroma factoids

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)

Neuroma

Post-traumatic proliferation of nerve cells. Not a real tumor.
No perineural lining or fibroblastic tissue.

Can occur after:
Nerve avulsion (C-spine)
Operative beds
Limb amputation.
Look like small Schwannomas on imaging.

Dural mets sources

Predominantly
Lung
Breast
Prostate
Melanoma

Chunky thickening of dura on imaging.

Can even spread on top of meningioma.

Choloroma definition

Granulocyte sarcoma
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

Benign.
Usually in lateral ventricle
Enhances markedly.
Can calcify.
Some association with Sturge-Weber syndrome (often ipsilateral to vascular malformation in this case)

Choroid plexus xanthogranuloma

Centered on glomus in lateral ventricle
May have fat density in it.
Often bright on DWI

Choroid plexus neoplasms

Papilloma
Carcinoma
Ependymoma
Hemangioma
Lymphoma
Meningioma
Mets

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.

CNS Teratoma

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)

CNS Lipoma factoids

Not true neoplasm.

Look for entirely fat signal and fat suppression on MR

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.

Medulloblastoma/PNET

Comprise about 1/3 of posterior fossa tumors, 50% of cerebellar tumors.

Very malignant, WHO grade IV

Melanotic type has worse prognosis.

Medullomyoblastoma

Look like regular medullablastoma. Myogenic features on histology.

Rhabdoid tumor WHO grade

WHO grade IV, highly agressive. Death within 1 year.

Ependymoma prognosis

Filum terminale best (WHO I)
Cord
Supratentorial space
Posterior fossa worst (WHO II)

High rate of seeding.

Subependymoma factoids

WHO grade 1
Look like ependymoma in every way except location.
Frequently multiple.
Lateral ventricular arise later in life (>15 or so)

Cerebellar liponeurocytoma

Mean age 51
Gross fat can be seen.
Otherwise look like medulloblastomas.
Good prognosis

CNS hemangioblastoma

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

CNS
Hemangioblastomas
Cerebellar
Retinal
Spinal
Medullary.
Extraaxial
Renal
Cysts
Hypernephroma
Hemangioblastoma
Adenoma
Pancreas
Cysts
Adenoma
Adenocarcinoma
Islet cell tumor
Liver
Hemangioma
Cyst
Adenoma
Spleeen
Angioma
Adrenal
Pheochromocytoma
Cyst
Lung
Cyst
Bone
Hemangioma
Endolymphatic cell tumor
Cardiac
Rhabdomyoma
Epididymis
Cyst
Cystadenoma
Polycythemia

CNS Mets factoids

Usually well defined with a lot of edema.
Mostly near G/W junction.

Hemorrhagic CNS mets

Breast CA
Choriocarcinoma
Lung CA
Melanoma
RCC
Retinblastoma
Thyroid

Calcified CNS mets

Chondrosarcoma
Mucinous adenocarcinoma
Breast
Colon
Ovary
Stomach
Osteosarcoma

Calcified CNS primary tumors

Astrocytoma
Choroid plexus papilloma
Craniopharyngioma
Ependymoma
Gangliglioma
Meningioma
Neurocytoma
Oligodendroglioma
Pineal tumors
Any post radiotherapy.

Features of bleed from occult cavernoma

Edema only early on, resolves by 8 weeks
Resolving mass
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
Calcification rare.

Pleomorphic xanthoastrocytoma

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.

Medulloepithelioma

WHO grade IV
Occur in infants
More supratentorial, but can in infra
Locations
Temporal more than parietal, even in globe
With progression develop pretty much any appearance, cysts, calcification, necrosis, enhancement, eventually subarachnoid dissemination

Ependymoblastoma/PNET grading

WHO grade IV Death 6-12 months.

Ganglioglioma factoids

Usually present with seizure
Benign, Slow, Bony remodeling
Worse prognosis with higher metabolism on PE
Has some glial differentiation

Gangliocytoma factoids

No actual glial component, so no potential for malignancy unlike gangligliomas.
Very jellylike.

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.

Astrocytoma factoids

Most frequent primary solitary intra-axial mass in adult

Anaplastic astrocytoma

Evolve from lower grades
Often predated by diffuse astrocytoma.
Mean transformation to GBM is 2 years.

GBM factoids

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
medulloblastomas
Cowden
cerebellar gangliocytoma
vHL
Li-fraumeni
Astrocytomas>PNET>Chroid plexus tumor
Mafucci
NF1
NF2
Ollier
Tuberous sclerosis
Turcot
Glioblastoma>>meduloblastoma

Temproal lobe neoplasms

Gangliglioma 0-30
Astrocytoma, low grade 0-30
DNET 10-20
Oligodendroglioma 30-60
PXA 10-35
Desmoplatic infantile gangliglioma 0-1

Gliosarcoma

GBM variant, about 2%, very nasty
Prefers supratentorial space.
Can be well defined, superficial and well enhancing

Multicentric astrocytoma

May be metachronous or contiguous spread
Associated with NF1

Corpus Callosum masses

Neplasm
GBM
Lymphoma
Mets

Demyelinating
MS
PML
Adrenoleukodystrophy
Marchiafava-Bignami disease
PRES

Acute shear injury
Stroke
Lipoma

Subependymal giant cell astrocytoma

Another glioma variant
Classically associated with tuberous sclerosis.
WHO grade 1

Central neurocytoma

WHO grade II
Frequent calcification, cystic
Location: favors lateral or 3rd ventricle
Edema is rare
Peak in third decade.

Oligodendroglioma factoids

WHO grade II
Looks very similar to central neurocytoma but age peak is different

Anaplastic oligodendroglioma

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

Chordoid glioma

WHO grade II
Slow growing, solid, well circumscribed, enhancing
Mass effect may cause hydrocephalus

Astroblastoma

Rare
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

Angiogtopic variant
Infarct-like lesions
Focal parenchymal enhancement and/or dural enhancement
Multifocal

CNS Sarcoma

Meningeal types are most frequent (Meningo, fibro, etc.)
From there invade the brain.
Acts like GBM and sarcoma rolled into one.
Location
Favor temporal lobe with invasion of dural surfaces.

Germinoma factoids

aka Seminoma

CSF seeding is common
Can have cystic component (esp if in unusual location, in which case not as radiosensitive)

Choriocarcinoma

Distinctly commonly hemorrhagic
Uniquely + hCG and placental lactogen.
High rate of subarachnoid seeding

Pineoblastoma factoids

Peak in 1st decade
WHO grade IV
Highly cellular (round cells)

Pineocytoma

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

Colloid cyst

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

Neuroepithelial cyst

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

Choristoma

Mass of neural tissue in abnormal location (hamartoma type thing). Have vascular and fibrous tissue.
May enhance.
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

CNS post-op

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
demyelination
Ca No No Yes, peds
Necro Leuko No No Rare, after chemo
Reversible Yes Yes No
Telangiectasia No No Yes
Hemorrhage No No Often

Demyelination.
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

NASCET definiton of carotid stenosis

% stenosis = 100 x (distal nl lumen-resid lumen)/distal

ECST definition of carotid stenosis

%stenosis = 100 (estimated true lume-resid lumen)/estimate

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

Infarct
Abscess
Cortical spreading depression
Lymphma, Epidermoid, PNET
MS
Metabolic disease (Canavan's)
Seizure
Severe hypoglycemia
Trauma

Cerebral blood flow

Normal is 45-110 ml/min/100g of tissue
20-40 is oligemia- underperfused but enough for survival
<20 action potentials cease
About 10 or less, death occurs.
rCBF = rCBV/rMTT

Infectious CNS vasculitis

Haemophilus influenzae
Syphilis
TB
Herpes Zoster
HIV
and others