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NEURORADIOLOGY

EMBRYOLOGY:

the telencephalon and diencephalon are part of the forebrain. The forebrain is derived from the prosencephalon. The midbrain originates from the mesencephalon. The hindbrain originates from the rhombencephalon

BIT ON REFLEXES:

jaw: c5 biceps: c5-6 triceps: c7-8 finger: c7-t1 quads: L2-L4 hamstrings: L5-S2, ankle jerk: L5-S3, toe flexion reflex: s1-s2

Cerebral vasular territories Click here

CC fistula:

can see retrograde flow in the superior ophthalmic vein and flow into the contralateral cavernous sinus

BASAL GANGLIA MR IN PTS WITH LIVER DISEASE:

see increased T1 and decreased T2

BUPHTHALMOS IN PTS WITH NF1:

due to sphenoid wing dysplasia and herniation of temporal lobe

VEIN OF GALEN:

posterior and superior to 3rd venticle

MOST COMMON CAUSE OF AN ENLARGED MASSA INTERMEDIA:

only one that i know of is chiari 2

DOES POSTERIOR CHIASM LESION LEAD TO BITEMPORAL  HEMIANOPSIA?

need to check this. It looks like both anterior and posterior chiasmal lesions will produce bitemporal hemianopsia while lateral lesions will produce heteronymous hemianopsia

RETINAL LESIONS:

vhl: retinal angiomas (von hippel tumor)

sw: choroidal angiomas

nf1: lisch nodules (pigmented iris hamartomas), Note that in nf2, there are no Lisch nodules

ts: retinal hamartomas (phakomas) (astrocytic proliferation in the optic disc which is usually bilateral)

downs: brushfield spots on the iris

VHL ASSOCIATIONS:

von Hippel-Lindau disease is an autosomal-dominant disorder linked to a defect on the short arm of chromosome 3. It is a multisystem disease characterized by cysts, neoplasms of the abdominal viscera, and hemangioblastomas of the central nervous system. Renal cell carcinoma is the most frequent malignant tumor. Pheochromocytomas are found in 10% to 15% of cases. Pancreatic manifestations include islet cell tumors and pancreatic cysts.

TUBEROUS SCLEROSIS:

AD, chromosome 16 short arm, classic triad of zits, nitwits, fits, 95% of them have cortical tubers, subependymal GCT near foramen of monroe, retinal phakomas, facial angiofibromas, shagreen patches, kidney cysts, cardiac rhabdomyosarcoma, liver adenoma, bone islands

If you need more detail, here is the scoop in TS (quoted from http://www.med.uc.edu/neurorad/webpage/files2.html):

Clinically these patients present with the triad of seizures (90%), mental retardation (50%), and adenoma sebaceum (90%).
-autosomal dominant, 1/10,000-1/50,000
-chromosomes: TSC 1 9q, TSC 2 16p- forme fruste 5x more common
-criteria (need 1)
        -facial angiofibromas
        -ungual fibroma (17%)
        -retinal hamartoma
        -cortical tubers (50%)
        -subependymal nodules
        -multiple renal AML
-presumptive (need 2)
        -hypomelanotic nodules
        -shagreen patch
        -single AML
        -multicystic kidney
        -cardiac rhabdomyoma (30-50%)
        -LAM pattern, honeycomb lung
        -first degree relative with TS
-subependymal giant cell astrocytoma in 15% (WHO grade I)
-other findings: retinal benign astrocytic hamartoma, heterotopias, myelination disorder, ventriculomegaly

NEUROFIBROMATOSIS

NF1: nf of cn3-12

NF2: trigeminal > facial. There are bilateral 8th nerve masses at the origin of the superior and inferior division of the vestibular nerve. The olfactory and olfactory nerve have no schwann cells and so are not affected. NF is also associated with moya moya (puff of smoke) (see below)

MOYA MOYA ASSOCIATIONS:

The Moya moya pattern of vessels seen on angiography is thought to be a phenomena secondary to intracranial large vessel narrowing or stenosis. The response of the cerebral vasculature to this type of narrowing is for more distal vessels to proliferate. There is debate as to whether the vascular abnormality represents a congenital problem or an acquired stenosis of intracranial vessels that occurs early in life. Moyamoya type changes have been found in a variety of diseases, including sickle-cell disease, neurofibromatosis, trisomy 21 and fibromuscular dysplasia. Other predisposing conditions for this problem include an auto immune process, cranial trauma, anaerobic bacteria or the use of oral contraceptive but none has been convincing.

WALLENBERG:

also called lateral medullary sydrome. It is due to PICA or vert dissection or infarct. Note that Weber is from PCA infarct. Wallenberg produces pain and temp loss from the ipsilateral face and numbness and impaired sensation in the ipsilateral body. There is contralateral body pain and temperature loss and numbness (from the lateral thalamus)

For some more detail:

classically as mentioned above it results from PICA infarct most usually due to vert artery occlusion.

ipsilateral: preganglionic horners, face pain, numbness, and decreased sensation. Also dysphagia, hoarseness, decreased gag reflex, decreased taste, vertigo, nystagmus, n/v, diplopia, hiccups

contralaterally: numbness, decreased pain and temperature sensation in trunk and extremities horners with meiosis, ptosis, anhydrosis

EFFECT OF STURGE WEBER ON THE CHOROID PLEXUS:

ipsilateral choroid plexus enlargement is seen in Sturge Weber

PAPEZ MEMORY CIRCUIT (REMEMBER THIS ONE!):

this circuit describes the connections that cause temporal lobe seizures. The following components comprise this circuit:

1. hippocampus, 2. parahippocampal gyrus, 3. fornix, 4. mamillary bodies

SKETCH OF THE CAVERNOUS SINUS (CORONAL) WITH CONTENTS SHOWN:

the ica is most medial, and cn6 is the next most medial. The rest are in the wall. V2 is the most lateral

IN HIV CNS INFECTION:

Involves oligodendroglia: PML

Involves endothelial cells: herpes

Involves perivascular spaces: cryptococcus

Most common brain infection in HIV: HIV

Most common opportunistic infection: Toxo

overall, the most common cns infection in hiv are as follows:#1 is cmv, #2 is hiv and #3 is jc virus (pml) for diffuse and for focal is toxo

BRIGHT BASAL GANGLIA ON T1:

this is associated with liver disease, manganese toxicity, and tpn

HYPOINSTENSE BASAL GANGLIA ON T1:

The bilateral basal ganglia lesions are similar in appearance to cyanide and carbon monoxide poisoning, two "acquired" mitochondrial cytopathies (which uncouple the cytochrome chain). Leigh's disease (also known as subacute necrotizing encephalomyelopathy) has an infantile, juvenile and adult type. (quoted from radiologyweb.com)

THE LIPODYSTOPHIES (quoted from radiologyweb.com):

Adrenoleukodystrophy is an X-linked disease. The disease is caused by peroxisomal enzyme deficiency. The three major types are adrenoleukodystrophy, adrenomyeloneuropathy, and adrenoleukomyeloneuropathy. Adrenoleukodystrophy is associated with bilateral demyelination in the peritrigonal area and corpus callosum, which display marked enhancement post contrast. It is the most common form of the three and onset is usually at the age of three years. Adrenomyeloneuropathy is the second most common and is characterized by young adulthood onset. Adrenoleukomyeloneuropathy is characterized by peripheral nerve and spinal cord involvement. Krabbe's disease is autosomal recessive, and results from a lysosomal deficiency. Imaging studies demonstrated demyelination of centrum semiovale and corona radiata. Hyperdensity of the thalami on CT has also been described. Metachromatic Leukodystrophy, is an autosomal recessive disease, resulting from lysosomal deficiency of arylsulfatase A. It is characterized by symmetric periventricular white matter disease which is greatest seen in the frontal lobes. It is noteworthy because it is the most common leukodystrophy. Alexander's Disease often enhances but typically affects the white matter of frontal lobes preferentially. It is associated with macrocephaly. Canavan's Disease- (van Bogaert-Bertrand disease) results from a deficiency in N-acetylaspartylase. It is transmitted in an autosomal recessive manner. The disease is distinguished from other leukodystrophies in that it involves the subcortical U fibers and only the internal capsule is spared. Like Alexander's Disease, Canavan's Disease is associated with macrocephaly. The occipital lobes are preferentially involved.

This is what the neuro fellow at Yale had to say about the leukodystrophies:

approach:

in the infant there are only 3 to think about:

canavan

alexander 

krabbe

of these 3, canavan and alexander have a big head and krabbe has a normal sized head

in the older child or adult:

male:

think about adrenoleukodystrophy and metachromatic leukodystrophy

since these are all X linked recessive, if you see it in the female, then consider wrong karyotype

of the above, only 2 enhance: canavan and adrenoleukodystrophy

of the above, alexander has a frontal predominance

adrenaleukodystrophy tends to edge enhance. Typically, posterior to anterior with sparing with the cortical U fibers which is pathognomonic. It is X linked ie males only.

Some other things that were mentioned are PVL in infant where you see WM thinning periventricularly with resultant enlargement of the ventricles

PML does not enhance. Papovirus is the etiology

MS classically involves the cerebellar peduncles. It has WM lesions that are perpendicular to the ventricles

SYRINGOMYELIA: 

involves spinal cord, while syringobulbia involves brainstem

CLASSIFICATION OF SPINAL END PLATE CHANGES:

Type 1) Granulation tissue--which gives signal of increased water: Hypo on T1, hyper on T2
Type 2) Fatty change--which gives signal of increased fat: Hyper on T1, hyper on T2
Type 3) Sclerotic change--which gives signal of increased calcium and decreased water and fat: Hypo on T1, hypo on T2.

ASSOCIATIONS WITH AGENESIS OF THE CORPUS CALLOSUM:

Dandy Walker 11%, midline lipoma 10%, chiari two 7%. If it occurs by itself, it may be assymptomatic. It is associated with CNS anomalies (85%), cardiac and GU anomalies (15%), and karyotypes 13, 15, 18. If it is diagnosed after 22w than you see "teardrop ventricles". A high 3rd ventricle and radial array of gyri are associated

CHIARI MALFORMATION:

C1 has herniated cerebellar tonsils and syringomyelia; Cerebellar tonsillar ectopia of > 5 mm (adults and children), syringomyelia 20-30%, hydro 25-44%, and Klippel feil 10%

C2 has partial absence of the septum pellucidum,  or complete absence in 40%. There is dysgenesis of the CC in 80%. Usually the splenium and rostrum is missing in 80-90%. Also there is an elevated 3rd ventricle. In addition, there is scalloping of the petrous bone and clivus. The massa intermedia and foramen magnum are both enlarged; skull and dura: small posterior fossa, luckenshadel skull, fenestrated falx, gaping foramen magnum, concave clivus and vents: hydro 90%, elongated tube like vents, high riding 3rd ventricle, absent or hypoplastic CC. The foramen magnum may be enlarged

In C2 the brain shows inferior displacement of the vermis, medullary kink, large massa intermedia, tectal beaking, towering cerebellum through a wide tentorial incisura, associated polymicrogyria, callosal dysgenesis, interdigitating sulci, meningiomelole 100% which is usually consists of protrusion and exposure of the neural tissues through a spina bifida defect

C3: there is herniation of the cerebellum into a high cervical or occipital encephalocele + all features of C2

C4: extreme cerebellar hypoplasia, no displacement. This includes hypoplasia of the pons in addition to agenesis of the cerebellum

NOW FOR THE ABOVE IN MORE DETAIL (quoted from http://www.med.uc.edu/neurorad/webpage/files2.html):

CHIARI 1:

3mm below ="mild tonsillar ectopia"- no clinical significance, 3-5mm gray area, >5mm= Chiari I- may have cranial neuropathy due to brainstem compression, central cord syndrome due to syrinx.

Chiari I is by far the most common of the Chiari malformations. Etiologic theories include embyologic anomaly of craniocervical junction, intrauterine tonsillar herniation due to hydrocephalus, or acquired deformity from platybasia/basilar invagination. Associations include hydromyelia (25-60%), basilar invagination (25-50%), C2-3 fusion (18%), AO fusion (10%), cervical occulta (5%), Klippel-Feil (5%).

No association with brain anomalies unlike Chiari II.

CHIARI 2:

Chiari II malformation is a relatively common congenital CNS anomaly which represents an abnormality of neural tube closure at aproximately 4 weeks of gestation. The most common anomaly due to defective neural tube closure is anencephaly. The basic abnormality in Chiari II malformation is inadequate developmant of the fourth ventricle with a resultant small posterior fossa. The associated findings are largely due to the small posterior fossa. Myelomeningocele is almost universally present with this anomaly. The condition can be hereditary and familial. Chiari II is in no way related to Chiari I.
Associated intracranial findings (variable and rarely all present):
    -hydrocephalus, narrow aqueduct, large foramen magnum
    -lacunar skull- inner table scalloping- resolves after about 6 mo
    -scalloped posterior petrous/clivus
    -low tent, wide hiatus
    -hypoplastic falx with gyral interdigitation
    -vertical straight sinus
    -lateral vents parallel with colpocephaly and squaring of frontal horns
    -80% absent septum pellucidum
    -hourglass 3rd vent with large massa intermedia
    -long, low and small 4th vent
    -beaked tectum with large QP cistern
    -large caudate heads
    -towering cerebellum
Extracranial findings:
   ->99% with myelomeningocele
   -70% with deficient C1 posterior arch
   -restrictive dural band at craniocervical junction
   -20% with diastematomyelia (20%)
   -50% hydromyelia 
   -thoracolumbar kyphosis

DANDY WALKER:

In DW, there is complete vermian agenesis while in DW variant , there is mild hypoplasia of the vermis. Agenesis of the corpus occurs in 20 to 25% 

ETIOLOGY OF DWM:

There is atresia of the foramina of Magendie and insults to the development of the cerebellum and 4th ventricle. Cisterna magna is insult to the developing 4th ventricle. DWV is insult to the developing cerebellar hemispheres and DW is a combination of both

HOLOPROSENCEPHALY:

Septum pelucidum is always absent. Single ACA. The SS, SSS, internal cerebral veins as well as falx are absent. The ddx: severe hydro, DW cyst. hydrancephaly, agenesis of the CC with a midline cyst. Since the CC forms from anterior to posterior, and the posterior portion is present in holoprosencephaly, this implies that the anterior part is lost as opposed to not forming in the first place

It is common to all types is fusion of grey matter across the midline. Facial anomalies are frequently associated with the lobar type. The semilobar type may absence of the body and genu of the of the corpus callosum with an intact appearing splenium. Septooptic dysplasia is thought to be a mild form of holoprosencephaly

CAVUM SEPTUM:

cavum sp: 5th ventricle, cavum vergae: 6th ventricle which is a posterior extension of the CSP behind the foramen of monro

CORPUS CALLOSUM:

development is generally  from front to back except for the rostrum. Note that callosal agenesis is associated with radial orientation of the gyri along the medial hemispheres. Partial agenesis is associated with Chiari 2, holoprosencephaly. In Dandy Walker, agenesis of the CC occurs in about 20%

MOST COMMON CPA MASS:

Most common CPA mass: vestibular schwannoma

PINEAL REGION TUMORS:

The majority of pineal region tumors are not of parenchymal cell (ie pinealoblastoma, pinealocytoma) origin. Most are of germ cell origin and occur in predominantly in teenagers

germ cell (>50% of pineal tumors, ie most common of pineal tumors): 

germinoma is #1 and has engulfed Ca++

teratoma is #2 (ie is the second most common pineal mass) and is heterogeneous with fat and cystic areas: The tumor elevates the internal cerebral veins and the patients present with Parinaud's syndrome

parenchymal:

pineocytoma: looks like normal pineal parenchyma with exploding Ca++

pinealoblastoma: exploding Ca++ and also associated with trilateral retinoblastoma

others: pineal cysts, astrocytomas, meningioma, vein of galen

PINEAL CA++

seen on 60-70% of plain skull films. Pineal Ca++ at < 6 years old is abnormal

FALCINE CA++:

falx ca++ is more common in males. Dural Ca++ is more common in females.

BG CA++:

normal if seen on CT but abnormal if seen on plain film (suggests hypoparathyroidism, pseudohypoparathyroidism, cockayne, wilsons dz)

MAGNETIC SUSCEPTIBILITY:

magnetic susceptibility is greater with conventional T2 than with FSE T2

WHAT IS THE FORAMEN OF VESALIUS?:

it is posterior to the rotundum and contains the emissary veins. Note that the foramen lacerum is a fibrous structure through which nothing passes

JUGULAR FORAMEN:

It contains 10 (medially), 11, and the jugular vein. Anterior, medial and smaller is CN9

THIRD NERVE PALSY:

DM, MS, p.comm or basilar artery aneurysm (causes dilated or blown pupil in the case of unruptured aneurysm), migraine, lymphomatous memingitis. It is better to think of it as pupillary sparing=DM, and pupillary dilatation= unruptured p comm aneurysm. Weber syndrome is due to p comm infarct causing ipsilateral pupillary dilatation and contralateral hemiparesis

CLASSIC CAUSE OF ADEM:

measles

HOMONYMOUS HEMIANOPSIA:

lateral geniculate and occipital lobe lesions

PITUITARY MICROADEMONA:

by definition: <1cm

PINEAL TUMORS:

germ cell tumors (eg germinomas, yolk sac tumors, choriocarcinomas) are more common than non germ cell tumors (eg pinealocytoma, pinealoblastoma). Germinomas almost always occur in the teens and are rarely seen after 30 years old. Males outnumber females by about 9:1

PERINAUD'S SYDROME:

due to tectal compression by mass usually teratoma. There is loss of upward gaze due to pineal region tumor. Also there is deficiency of pupillary dilatation and reduced light response

PATTERNS OF MYELINATION OF THE BRAIN:

Myelination on T1 imaging (months):

0 posterior limb of internal capsule and decussation of superior cerebellar peduncles

2 anterior limb of internal capsule

3 cerebellar WM

4 splenium

6 genu

8 adult pattern

on T2 imaging, myelination lags behind the appearance on the T1 images. For example, the adult pattern of myelination appears at 24 months instead of 8 months on T2 weighted imaging

SYNOVIAL CYST:

most common in the L spine

TARLOV CYST:

These represent the most common type of arachnoid cyst. They arise from the posterior rootlet (S2 and S3 most common) and form a dilated nerve root sleeve as a normal variant. They can cause sacral erosion and may communicate with the thecal sac

CONGENITAL INRADURAL CYSTS:

arachnoid cysts are the most common and are found in the thoracic region dorsal to the spinal cord. Neurenteric cysts are usually anterior or anterolateral to the cord. Spinal neurenteric cysts may enlarge the spinal canal

CHORDOMA:

in the head and neck, spenoocipital sychondrosis is favored site of origin of chordomas. Chordomas are bright like csf on t2. They are calcified in up to 50%. The most common site of origin is the sacrococcygeal region

INTRAVENTRICULAR LESIONS:

intraventricular lesion location:

colloid cyst: anterior 3 vent

subependymoma: posterior 3 vent

craniopharyngioma: inferior to 3 vent

choroid plexus papilloma: lateral vent (atrium)  

this is how radiologyweb.com describes ependymomas vs subependymomas: 

subependymomas (also known as subependymal glomerate astrocytomas) are usually incidental fourth ventricular lesions in middle-aged or elderly men. Ependymomas are most commonly seen in children and typically in the 4th ventricle. In spine of adult, ependymoma>astrocytoma. In spine of child, astocytoma>ependymoma. In brain of child, ependymoma is more common than in adults

MORE ON INTRAVENTRICULAR LESIONS:

about 10% of cns neoplasms are partly or totally intraventricular. The most common lat vent mass is a CPP. The most common 3rd vent mass is a colloid cyst. The most common 4th vent mass is an ependymoma

COLLOID CYST:

anterior 3rd vent originating from roof near foramen of monro. They may sometimes show peripheral capsular enhancement, and moderate hydrocephalus

CHOROID PLEXUS PAPILLOMAS:

The body and atrium of the lateral ventricle are favorite loci for choroid plexus papillomas, particularly in young children. The 4th ventricle is most common in adults.

MENINGIOMA:

most commonly supratentorial. parasagital>convexities>sphenoid wing>CPA>olfactory groove>planum sphenoidale. The most common intraventricular location is atria of  lateral ventricles. Interestingly, ventricular meningiomas are always in the L lateral ventricle Meningiomas are supplied by the ECA. The dural tail sign is not specific for meningioma. Meningiomas are the most common benign intracranial tumors and the most common extraaxial tumor in adults. If seen in childhood, than they are frequently associated with NF2

MULTIPLE ENDOCRINE NEOPLASIA:

men1 (wermer): pituitary adenoma, pancreatic islet cell tumor, parathyroid adenoma/hyperplasia. MEN 1 can have shwannomas, multiple lipomas, thymomas and carcinoids.

men2 (sipple): pheochromocytoma, thyroid medullary ca, parathyroid adenoma/hyperplasia. MEN 2a has associations with gliomas, GBM, meningiomas

men3 (synonymous with 2b): pheochromocytoma, thyroid medullary ca, facial neuromas. MEN 2b can have associated marfanoid features and hypotonia

Note that both Men 1 and Men2a and b are AD 

BRAINSTEM CRANIAL NERVE ORIGINS:

midbrain or above: cn1-4

pons: cn5-8

medulla: cn9-12

CALCIFIED POSTERIOR FOSSA MALIGNANCIES:

calcifications in posterior fossa malignancies:

medulloblastoma 10-20%, ependymoma 50%

astrocytoma: 60% in posterior fossa are calcified and of these 40% in the cerebellum and 20% in the brainstem are calcified. 40% of supratentorial astro's  are calcified

THE MOST COMMON PRIMARY LESION OF THE POSTERIOR FOSSA IN AN ADULT:

hemangioblastoma. Multiple lesions are seen in pts with VHL. These tumors occur exclusively in the cerebellum, and they are solid in 30 to 40%. Signal voids can be seen adjacent to or within the solid nodule component

INTRACRANIAL TERATOMA:

occur exclusively in males. They vary from benign to malignant. The pineal region is the most common site for teratomas. May contain fat. Associated with Parinauds

CHILDHOOD GLIOMAS:

10% of childhood gliomas are in the brainstem

BEST SEQUENCE TO SEE AN MS PLAQUE:

T2SE

SPINAL CORD LESIONS:

ependymoma: 60-70% (it is the most common spinal glioma across all age groups)

astrocytomas: 30% (it is the most common pediatric spinal glioma)

hemangiomas: 2%

note that in the spine of a child: asto 60%, ependymo 30% and in the spine of adult: astro 30%, ependymo 60%; note also that ependymomas are more common overall in children than adults

the spinal cord is the second most common site for mets after brain

note that in adult, spinal astrocytomas are more common than in children and in children, brain astrocytomas are more common than in adults

SPINAL MENINGIOMA:

the most common site is the thoracic spine

SPINAL TERATOMA:

most are congenital sacrococcygeal teratomas

MOST FREQUENT CAUSE OF INTRAMEDULLARY METS:

lung ca

DEVIC SYNDROME:

this is transeverse myelitis accompanied by blindness

SPINAL MS:

most plaques involve the lateral columns and are not usually found in the anterior or posterior columns

SPINAL INFARCT:

occlusion of the anterior spinal artery is more likely to be symptomatic than occlusion of the posterior spinal artery

BRAIN EPENDYMOMA LOCATION:

magendi>luschka

THE DREADED ANTONI A AND ANTONI B STORY:

this is somewhere in the depths of the AFIP notes which i have not yet opened. This story applies to schwannomas. The B cells are responsible for the cystic changes. Based on this, cyst formation is more common in shwannomas than in neurofibromas. In the absence of cyst formation, neurofibromas and schwannomas are indistinguishable by imaging

NERVE SHEATH TUMORS:

involves thoracic and lumbar spine most commonly. The plexiform neurofibromas can undergo malignant degeneration

MORE ON SCHWANNOMAS:

in spine, solitary benign neural tumors are almost always schwannomas. Schwannomas are common in sensory roots as single lesions. In NF, lesions are usually multiple and associated with NF1

LOCATION OF OPTHALMIC ARTERY:

ophthalmic artery passes through the optic canal and not the superior orbital fissure

PCA VS HEUBNER:

pca supplies thalamus via thalamic perforators. Does not supply cerebellum. Supplies occip, post temporal and parietal lobes

Heubner supplies caudate and ant inf internal capsule (it is a branch of the aca)

THIRD NERVE PALSY:

pupillary sparing 3rd n palsy is from DM. If pupil involved usually aneurysm or mass. Pupillary fibers run on outside of the third nerve

CIRCLE ANEURYMS:

anterior circulation 90%

A comm (35%)> ICA-Pcomm (35%) > MCA (20%) > basilar (5%) > other (5%)

distal to the circle the prevalence is only 2%

note that 20% of them are multiple and 25% of them are giant

CAROTID BRANCHES:

cervical: none

petrous: tympanic, pterygoid

cavernous: meningiohypophyseal, anterior meningeal, branch to trigeminal ganglion, dorsal meningeal, inferior hypoglossal, tentorial branch of bergorfundi

supraclinoid: OPA or ophthalmic, Pcomm, anterior choroidal. The anterior choroidal supplies the medial globus pallidus, optic tract, temporal lobe, amygdaloid nucleus, choroid plexus of the lateral ventricle

STROKES:

MCA (70%) > PCA (10%) > ACA (4%). The infratentorial vertebrobasilar PICA 10%

ARTERIAL TERRITORIES SEE THE FIGURES UNDER THE ANGIO SECTION ABOVE):

ACA:

-A1 segment: recurrent artery of Heubner comes off A1 and supplies the anterior limb of the internal capsule, putamen, anteror and inferior caudate head. One source says that the more common origin for the Heubner is A2 segment

-acomm

-A2: pericallosal and callosomarginal

MCA:

-most lateral hemisphere. Most also supply the lentiform nucleus

-M2: lateral brain (insular branches)

-M1: lenticulostriates from the horizontal portion of the M1

PCA:

-posterior third of inferior temporal lobe, and occipital lobe. It participates in the posterior limb of the internal capsule

HYPERDENSE TUMORS:

lymphoma, medullo, meningioma

BLEEDING TUMORS:

oligo, epend, gbm, medullo, pituitary adenoma

CALCIFIED TUMORS:

70% of intracranial oligodendrogliomas and 50% of medulloblastomas

CENTRAL NEUROCYTOMA:

young adults and no gender preference. It is located in lateral ventricle adjacent to the foramen of Monro. It is a well circumscribed lobulated mass with necrotic and cystic changes commonly seen. The tumor is of neuronal origin. Calcification is common. Iso on T1 and iso to hyper on T2. The ddx is: oligo, subependymal gc astrocytoma, low grade astrocytoma, ependymoma

PILOCYTIC ASTROCYTOMA:

nearly 50% of cerebellar astrocytomas are cystic with a mural nodule (enhancing)

RANGE OF CNS TUMORS IN TS:

subependymal gc astrocytomas located near the foramen of monro (can cause obstruction of csf flow), hamartomatous cortical tubers, subependymal heterotopic nodules (these represent heterotopic grey matter and may enhance on gad enhanced mri). Note that the gc astrocytomas commonly show calcification

OLIGO'S:

involve cortex and subcortical wm in the fronto parietal region. They commonly show ca++ and hemorrage and can also have cytic degeneration

INTRACRANIAL EPENDYMOMAS:

these are less common in adults than in children. Most are located in the parenchyma and not the ventricle. Have a fronto parietal predilection. Variable MR and CT contrast. Note that the majority of intracranial ependymomas are infratentorial. Posterior fossa ependymomas are most common in the first 5 years of life

METS:

4/5 are supratentorial, and 1/5 are infratentorial

MOST COMMON MASS IN THE ADULT BRAIN:

infarct. However, most common primary brain tumor is a hemangioblastoma. Most common malignancy is mets

4th VENTRICULAR TUMORS:

ependymoma, choroid plexus papilloma, medulloblastoma, astrocytoma

INTRAVENTRICULAR TUMORS:

CPP, CP carcinoma, meningioma, teratoma, ependymoma, subependymoma, neurocytoma (septal), vascular malformation, heterotopic grey matter, cysticercosis and echinococcal cysts

CHOROID PLEXUS PAPILLOMA:

seen more in the lateral vents more on the left side in children. In adults, they are seen more in the 4th ventricle.

GANGLIOGLIOMA:

more common in young pts, not elderly. They prefer the temporal lobes and the third ventricle. Clinically, the pts usually present with epilepsy. These tumors can be found as a posterior mediastinal mass in a child or young adult

CNS LYMPHOMA:

primary cns lymphoma is more common than secondary cns lymphoma. Focal intraaxial lesions are the most common presentation. With recurrence, leptomeningeal dz is more common. This can present with cranial nerve palsies. Ring like enhancement is not seen in non AIDS lymphoma. Primary CNS lymphoma is frequently multiple (20 to 40% of cases) and the BG is a common location. The lesions may show hypointensity on T2 weighted MR. About 1/3 of pts with systemic lymphoma get cns disease

STURGE WEBER:

V1 is associated with occipital angiomatosis, V2 is associated with parietal angiomatosis, and V3 is associated with frontal angiomatosis. In terms of which is most common: parietal > occipital > frontal. It is associated with hemiatrophy of the effected side of the brain. There is ipsilateral thickening of the skull, enlargement of the paranasal sinuses and mastoids (Dyke Davidoff)

MULTIPLE SCLEROSIS:

Rudik Red Flag: no eye findings, no clinical remission, no bladder involvement, no sensory signs suggest another diagnosis. MR is 97% specific. The most frequent location for the brain involvement is the periventricular WM. Optic neuritis is called Devic disease. 12% show no intracranial dz, Marcus gunn pupil is  central vision loss

MYCOTIC ANEURYSMS:

s. viridans > s. aureus

for oncotic aneurysms: think atrial myxoma and chroriocarcinoma

for sickle cell dz: staph aur > salmonella

PARASELLAR MASSES:

#1: pituitary adenoma

#2: craniopharyngioma

#3: meningioma (rare)

#4: paramedian carotid artery

Microadenoma are more common then macroadenoma clinically but macroadenoma are more common then microadenoma pathologically. Macroadenomas are more common in children

In peds: craniopharyngioma > visual pathway glioma > hypothalamic astrocytoma

adult: pituitary adenoma > craniopharyngioma > inflammatory pseudotumor from tolosa hunt

SUPRASELLAR:

common: rathkes cleft cyst, craniopharyngioma, subacute hemorrage

uncommon: lipoma, dermoid, congenital ectopic neurohypophysis

CHORDOMA:

homogeneously bright on T2 and heterogeneous and low signal on T1. They show Ca++ in 30-70%

BLEEDS:

with sdh and arachnoid cyts, the veins are pushed in against the brain, while in the elderly with atrophy, the veins bridge the csf space

FORMATION OF LIPOMOMYELOMENINGOCELE AND MYELOMENINGOCELE:

non disjuction causes a big defect which forms a myelomeningocele ie it is more severe. Premature dysjunction forms a small defect and fat gets in forming a lipomyelomenigocele. The lipo is occult and is the most common form of the occult forms. So think fat = occult

TETHERED CORD:

short fat cord below L2 in the adult by definition. At birth, the level is at L2,3 and in the adult, it is at L1,2

MR ARTEFACTS:

phase encoding direction: motion, truncation (ring down artefact at high contrast interfaces which decreases the resolution of the image. Decreasing  the contrast resolution of the image decreases this artefact. Also, fat suppression decreases this artefact

frequency encoding direction: chemical shift artefact.

FSE causes a decrease in contrast

PML VS HIV INFECTION OF THE BRAIN:

PML affects the subcortical U fibers while HIV does not

CEREBELLUM:

the nodulus is midline while the flocculus is not

SPHINGOLIPIDOSES:

ADL: (see Lorenzo's oil) in the occiput and progresses anteriorly. The leading edge of dysmyelination is enhancing

Alexander: dysmyelination disorder affecting the anterior frontal WM. It is associated with macrocephaly (alexander the great big head)

Canavan: also have a big head. Affects the occipital lobes more commonly

Krabbe: hyperdense lesions in the thalami, caudate, and Korona Radiata. This is due to abnormal Fe retention in the globus pallidus

MELAS, MERRF: look these up

Leighs: This is not a sphingolipidosis. It is AR. There is abnormality  in bilateral BG in particular putamen and lentiform nucleus. It is a grey mater lesion.

CONJOINED ROOTS:

these are most commonly in the L5,S1 level

WIDEST PART OF SPINAL CANAL:

occurs at C1

BG IN ALCOHOLIC LIVER DZ:

increased manganese causes an increase in the T1 signal and a decrease in the T2 signal

CAUSES OF HYDROCEPHALUS:

overproduction, obstruction, communicating, normal pressure hydrocephalus (ventricular dilatation out of proportion to the degree of sulcal effacement)

EXTERNAL CAROTID TO INTERNAL CAROTID ARTERY COLLATERALS:

vidian, artery of the foramen rotundum, facial and anterior deep temporal collaterals to the ophthalmic artery, meningolachrymal branch off the middle meningeal artery to the ophthalmic artery

EXTERNAL CAROTID TO VERTEBRAL ARTERY COLLATERALS:

ascending pharyngeal neuromeningeal division to vertebral artery and muscular branches of occipital artery to distal vertebral artery

TENORIAL MENINGIOMA:

must look at meningohypophyseal artery as this is most likely supplying it

CORTICOSPINAL TRACT:

the fibers for this tract pass through the posterior limb of the internal capsule

ARACHNOID CYST:

about 10% are infratentorial. The most common location in the posterior fossa is retrocerebellar. A suprasellar arachnoid cyst should be differentiated from an enlarged anterior 3rd ventricle. Scalloping of the bone adjacent to an arachnoid cyst is commonly seen

RATHKES CLEFT CYST:

may show a thin rim of enhancement. Hemorrage may occur within the cyst. Most of them are intra and suprasellar in location

PITUITARY MICROADENOMA:

enhance homogeneously with contrast. They are less than 1 cm in diameter by definition

CRANIOPHARYNGIOMA:

originate form Rathke cleft pouch. most are located in the intrasellar and suprasellar location. Cystic changes and calcification are common. They can sometimes have hemorrage within them

MOST COMMON CAUSE OF BACTERIAL MENINGITIS IN ADULTS:

Strep Pneumonia

CNS SARCOID:

chronic basilar meningitis is the most common type. Basilar meningitis is also the most common CNS manifestation of coccidioidomycosis

MOST COMMON CAUSE OF MENINGITIS IN PTS WITH AIDS:

cryptococcus neoformans. Infarction is a sequella of this infection

ORGANS MOST COMMONLY AFFECTED BY CYSTICERCOSIS:

muscle and brain

MOST COMMON CAUSE OF ENCEPHALITIS:

herpes simplex 1. It is usually a necrotizing encephalitis

FX OF PETROUS BONE:

causes 7th and 8th nerve palsy

SAH:

often associated with intraventricular blood. Traumatic SAH usually localizes in the interpeduncular fossa or subarachnoid space

SACCULAR ANREURYSM ASSOCIATIONS:

fmd, marfans, coarct, ehlers-danlos

GIANT ANEURYSM:

>25mm by definition. One half to 2/3 are found in the posterior fossa. About 20% of pts with aneurysm have multiple aneuryms

BEST WAY TO LOOK AT CAVERNOUS ANGIOMA:

MRI with gradient echo technique

DURAL AVF:

Cause symptoms related to intracranial venous hypertension, and may also be responsible for a thrombosed dural sinus

AVM'S:

have a nidus, typically have enlarged feeding arteries, and draining veins with av shunting, and may have associated aneuryms and hemorrage

ENHANCEMENT FOLLOWING INFARCT:

meningeal enhancement is seen within the first 3 days in large cortical infarcts and resolves after 1 week usually

CEREBRAL HEMORRAGE MRI APPEARANCE:

in hyperacute clots, oxyhemoglobin is present and appears isointense on both T1 and T2

by 24 to 72 hours, most intracerebral hematomas contain intracellular deoxyhemoglobin which appears isointense on T1 and hypointense on T2

during the early subacute stage, deoxyhemoglobin is converted to intracellular methemaglobin which appears hyperintense on T1 and hypointense on T2

During the late subacute stage, cell lysis occurs and methemoglobin is released into the extracellular space and appears hyperintense on both T1 and T2

In the early chronic stage, there is a low signal ring on T1 and T2 due to the presence of macrophages containing ferritin nd hemosiderin

A good pnemonic to remember this is DD-BD-BB-DD

MRA:

time of flight MRA relies on inflow of fully magnetized blood into the imaging plane and is encountered in flow compensated gradient echo images perpendicular to the axis of the blood vessel

phase contrast MRA generates MR vascular images by detecting changes in the bloods transverse magnetization as it moves along a magnetic field gradient

MYELINATION:

sensory fibers myelinate earlier than the motor fiber tracts

ADRENOLEUKODYSTROPHY:

X linked, involves long chain fatty acids in the blood. Involves the posterior portion of the hemisphere, the occipital lobes and visual pathway

METACHROMIC LEUKODYSTROPHY:

It is the most common inherited leukodystrophy

it is AR. Have deficiency of arylsulfatase A. There is an infantile and adult form. It is associated with nonspecific wm abnormality with progressive loss of hemispheric brain tissue and symmetrc low density WM adjacent to the ventricles. There is no contrast enhancememt

LEIGHS:

involves the putamen, caudate, and tegmentum which are increased in signal on T2. The pathologic changes are similar to Wernickes encephalopathy

ADEM:

involves both cerebral and cerebellar wm. Long term f/u is needed to exclude MS. It is initiated by a previous viral infection. Optic neuritis can be seen which is why it is sometimes difficult to distinguish from MS. It is more common in children then in adults

PML:

due to JC virus. M>F. Predilection for the occipital and parietal lobes. The spinal cord is rarely involved

DDX OF CENTRAL PONTINE MYELINOLYSIS:

pontine infarct, MS, Lyme, brainstem glioma

BIG HEAD ASSOCIATIONS:

canavan, alexander

MOST COMMON CAUSE OF DEMENTIA:

alzheimers. The hallmark is atrophy disproportionately involving the hippocampus

MOST COMMON MOVEMENT DISORDER:

parkinsons

TOXIC BRAIN DISORDERS:

central pontine myelinolysis: electrolyte imbalance

marchiafava bignami: tainted chianti causing necrosis of middle 2/3 of the corpus callosum; can also involve damage to the nearby subcortical wm and  anterior commisure

wernicke: thiamine deficiency with atrophy of the mamillary bodies

pallidal necrosis:  carbon monoxide poisoning

SOME SIGNS OF INCREASED ICP:

dorsum sellae erosion and erosion of posterior clinoids

PITUITARY FOSSA DIMENSIONS:

high: not > than 13 mm

ap diameter not > than 17 mm

TS AND AML:

80% of pts with TS have AML and 20% of pts with AML have TS. 75% of solitary AML occur in middle aged women

MENINGIOMA TYPES:

1: globular (this type is the most common)

2: meningioma en plaque (skull base)

3: multicentric (2-4%)

location:

convexity (lateral hemisphere) (20-34%) > parasagittal (medial hemisphere) (18-22%) > sphenoid ridge and middle cranial fossa (17-25%) > posterior fossa (9-15%)

meningiomas exhibit the "mother in law" effect with contrast. Ie they come early and stay late

Supply is almost always ECA"

vault (ie convexity): middle meningeal artery

sphenoid plane and tuberculum: recurrent meningeal br of the opthalmic artery

tentorium: meningeal br of meningohypophseal trunk of the ICA

clivus and posterior fossa: vert and ascending pharyngeal artery

falx: partly middle meningeal arteries and others

ICA supply is rare: intraventricular (choroidal vessels)

The hallmark of planum sphenoidale meningiomas is blistering adjacent to the sinus

SPINAL METS:

in children, the initial site of spread is spinal canal via the neural foramen

in adults, initial site is the vertebral body, typically posteriorly. Epidural space and pedicle are involved 2ary to vertebral involvement. Paraspinous ST changes are also frequently described. Distribution in the spine is according to distribution in the red marrow. Lower thoracic and lumbar spine are most frequently involved (source: Osborn)

SHEENAN:

sheehan is postpartum infarction of the anterior pituitary

CALLOSAL LIPOMAS:

2 types: tubular nodular is anterior, ribbon like is posterior. Note that 30% of lipomas occur in the callosal area

ROW OR HHT:

multiple cutaneous and visceral vascular abnormalities. Paradoxical embolie. Cerebral abscess. Epistaxis

KLIPPEL TRENAUNAY (KTS)

angioosteohypertrophy is another name for this

MENINGIOMATOSIS:

neurocutaneous angiodysplasia. Hamartomatous meningeal based lesions. Neurocutaneous melanosis. there is a 40% rate of developing primary malignant melanoma of the CNS

ETIOLOGY OF INTRACRANIAL ANEURYSMS:

common: hemodynamic injury, atherosclerosis, vasculopathy, high flow state

uncommon: trauma, infection, drug, neoplasm

INCREASED INCIDENCE OF INTRACRANIAL ANEURYSMS:

coarctation, anomalous vessels, PCKD, FMD, CTD,s eg Marfans, high flow state

THE 4 TYPES OF INTRACRANIAL VASCULAR MALFORMATIONS:

cavernous angiomas

venous malformations

capillary telangiectasia

AVM's (parenchymal or pial, dural, pial-dural)

POSITION OF CONUS:

tip of conus is at L1,2 while filum extends all the way to S1

CONCUSSIVE INJURY:

most common points of injury are anterior temporal lobe, inferior frontal lobe, parasagittal hemisphere, inferior brain stem

HERNIATION:

subfalcine: cingulate gyrus slips under the free margin of the falx and may result in contralateral ACA occlusion

transtentorial (uncal): ascending and descending. With descending, the parahippocampal gyrus is displaced medially over the tentorium and can result in PCA ischemia. the CPA cistern is enlarged and the suprasellar cistern is effaced. Can also get kernohans notch and Duret hemorrage

CONGENITAL ABNORMALITIES ASSOCIATED WITH DIFFERENT STAGES OF BRAIN DEVELOPMENT:

dorsal and ventral induction: anencephaly, encephalocele, meningomyelocele, chiari, holoprosencephaly, cerebellar hypoplasia

neuronal migration: lissencephaly, pachyhyria, schizencephaly, hemimegencephaly

neuronal proliferation: congential tumors, hydrancephaly, macro and micro cephaly, vascular malformation

neuronal histiogenesis: TS, NF, Sturge Weber, VHL

GLOMUS TUMORS:

skull base: glomus jugulare

below skull base: glomus vagale

at carotid bifurcation: carotid body tumor

PILOCYSTIC ASTROCYTOMA:

located most commonly in the 3rd and 4th ventrical. About half of them are in the optic chiasm or hypothalamus and one third of them are in the cerebellar vermis. They can cause obstructive hydro if in the 4th ventric or vermis

PLEIMORPHIC XANTHOASTROCYTOMA:

rare, located int the inferior temporal lobe. Cystic changes are common, and there is an enhancing mural nodule

GIANT CELL ASTROCYTOMA:

10 to 15% of pts with TS. Found near the foramen of Monro. Virtually never found elsewhere in the brain. Show strong heterogeneous enhancement with mixed hypo and isodense regions

OLIGODENDROGLIOMA:

most common intracranial neoplasm to calcify. They are almost exclusively tumors of adults. Pure ones are rare. Foci of cystic degeneration are common. They are predominantlu lesions of cerebral hemispheres and start in the white matter and grow towards the cortex. Theya re 85% supratentorial, with the frontal lobe being the most common location

GANGLION CELL TUMORS:

they are the transition between glial and non glial cell tumors

include ganglioglioma and ganglioneuroma as well as central neurocytoma. Ganglioglioma is more common than pure neural derived ganglioneuroma. Ganglioglioma is usually presenting as a cyst with mural Ca++ nodule; the most common clinical presentation is siezures. These occur most commonly in <30 yo, and most commonly supratentorially. The temporal lobe is more commonly involved then the frontal lobe

DDX OF INTRAVENTRICULAR TUMOR IN ADULT:

neurocytoma, giant cell astrocytoma, ependymoma, subependymoma, oligodendroglioma, low grade pilocytic astrocytoma

WHO MENINGIOMA GRADES:

1: benign (typical)

2: atypical

3: anaplastic (malignant)

PNET TYPE TUMORS:

medulloblastoma

neuroblastoma

pineoblastoma

ependymoblastoma

medulloepithelioma

BRAIN INFECTIONS:

TB: base of brain

herpes simplex: 2 is in neonates and is diffuse and 1 is in adults adn is in limbic sytem (temp, insular cortex, subfrontal, cingulate)

HIV: frontal

toxo: BG and cerebral hemispheres near the corticomedullary junction

crypto: meninges, BG, midbrain is the most common location

PML: multifocal areas of myelin and axonal loss involving the deep and superficial WM

CMV: periventricular rim. Ca++ seen in neonatal CMV

neurosyphilis: variable

an aside: primary lymphoma is periventricular. More than one lesion favors toxo. Periventricular location and subependymal spread favors lymphoma

TETHERED CORD:

most common cause is is lipoma. A thickened filum is usually associated. Other causes are diastematomyelia adn myelomeningocele. The presentation is pain, neurogenic bladder, spasticity, scoliosis

SPLIT CORD:

rare dorsal enteric fistula

neuroenteric cyst

diastematomyelia (T9 to S1)

with diast, the hemicords are separate in 50% and common in 50%. Thoracic: 20%, lumbar: 50%, combined: 20%. Diast is associated with Chiari 2, tethered cord, hydromyelia, hemivert, block and butterfly verts. An osseous spur is seen in 50% of diastematomyelia. F>M

ORIGIN OF NEURAL ELEMENTS:

ectoderm: skin and spinal cord

mesoderm: myotomes and intervertebral discs

endoderm: foregut, notocord (nuc of disc)

ENTEROGENOUS CYST:

most common location is the T spine (42% ) followed by the C spine (32%). The L spine is rare to be involved

DDX OF HERNIATED NUCLEOUS PULPOSIS:

conjoined nerve roots

perineural cysts

dilated root sleeve

schwannoma or neurofibroma

ARACHNOIDITIS:

empty thecal sac sign, clumped nerve roots (causes by intradural fibrosis)

DIFFERENTIAL OF RING ENHANCING LESIONS:

MAGIC DR: mets, abcess, gbm, infarct, contusion, demyelinating dz, resolving hematoma

BG CALCIFICATIONS:

physiologic (aging)

endocrine: hypo and hyperparathyroidism, hypothyroidism

metabolic: leigh, melas (mito myopathy, encephalopathy, lactic acidosis, and stroke), merrf (ragged red fiber thing), fahr (familial cerebrovascular ferrocalcinosis)

inflammation: histo, toxo, cmv

toxin: meoh, CO, lead

INTRASELLAR MASS:

pit adenoma, craniopharyngioma, mets, meningioma, aneurysm, rathke cleft cyst, pit hyperplasia, chordoma, pit abscess, empty sella, sarcoid

SUPRASELLAR MASS:

meningioma, craniopharyngioma, optic n and optic chiasm glioma, epidermoid, dermoid, germinoma, arachnoid cyst, infundibular tumor (mets, primary), hamartoma of the tuber cinereum

SUPRASELLAR MASS WITH CALCIFICATIONS:

giant carotid aneurysm, craniopharyngioma, meningioma, teratoma

PROCESSES PREDISPOSED TO CAROTID DISSECTION:

ehlers danlos, marfan, trauma, chiropractic manipulations, fmd, cystic medial necrosis

COMPLICATIONS OF CAROTID DISSECTION:

occlusion, embolus, aneurysm

MORE COMPLETE LIST OF INTRAVENTRICULAR NEOPLASMS:

ependymoma, neurocytoma, CPP, subependymoma, subependymal giant cell astrocytoma, tubers, mets, lymphoma, meningioma, colloid cyst, epidermoid, dermoid, medulloblastoma, germ cell tumor

PRIMARY CNS LYMPHOMA:

it will respond to steroids, while herpes encephalitis does not

NF AND MACROCRANIA:

this is most common with NF1

BROMOCRIPTINE:

pit fossa hemorrage is associated but it is not a common complication

MICROADENOMAS:

they are eccentrically located in the pituitary

ENHANCEMENT AFTER CVA:

you dont see meningeal or parenchmal enhancement 1 day s/p CVA. You see it after 4-7 d in non cortical infartions and after 6d in cortical infarctions

TUMORS THAT MIMIC ANEURYSMS:

in the posterior fossa: extraaxial lesions that most likely mimic aneurysms are accoustic neuromas and meningiomas.

intraaxial lesions that mimic an aneurysim are glioma, medulloblastoma, ependymoma, mets, and CPP

VENTRICULAR TEARDROP SIGN:

associated with agenesis of the corpus callosum

WHAT IS A METACHROMIC LESION?

it is a second lesion discovered subsequently and unrelated to the previous lesion

BINSWANGER DISEASE:

this is subcortical WM disease (arterioschlerotic encephalopathy). The principle etiology is HTN. Dementia is the cardinal feature, and there is demyelinization or partial necrosis of the cerebral WM in an occipital and frontal distribution

PEDIATRIC BRAIN STEM GLIOMAS:

common posterior fossa tumors. Mean age 10 years. 80% are anaplastic. 20% are low grade. pons>>midbrain>medulla

PILOCYTIC ASTROCYTOMA:

most common location is optic chiasm. optic chiasm>cerebellum> brainstem

PCA INFARCT:

affects ipsilateral thlamus, not the contralateral one

UNRUPTURED PCA ANEURYSM:

classically gives an isolated and complete 3rd nerve palsy while this is not seen with a PICA aneurysm

AMYLOID ANGIOPATHY:

this is deposition of amyloid in the media and adventitia of small and medium sized vessels of superficial layers of the cerebral cortex and leptomeninges with sparing of the deep grey nucei. It is not associated with systemic amyloidosis nor hypertension

PEAK INCEDENCE OF GLIOMAS:

seventh decade

MOST COMMON CAUSE OF CNS RHINORRHEA:

trauma. Osteoma of the frontal sinus can cause cns rhinorrea, but a mucus retention cyst cannot

ANENCEPHALY:

it is not associated with other major anomalies

HEMANGIOBLASTOMAS AND INTRACRANIAL BLEED:

hemangioblastomas do not typically bleed

MOST COMMON POST FOSSA MASS:

if i did not already say so, it is an infarct. The most common post fossa mass is mets. Hemangioblastoma is the most common post fossa primary tumor

MOST COMMON SPINAL CORD TUMOR IN CHILD:

astrocytoma (60%), ependymoma (30%), hemangioblastoma (3%)

THE ABC OF SPINE MR (N Tishkoff):

A: alignment

B: bone marrow

C: conus, cord

D: discs

E: endplates

F: foramina

TYPICAL MR BRAIN PROTOCOL USED IN OUR INSTITUTION:

sagital T1

flair

diffusion

3D time of flight

gad bolus neck

axial T1 gad