Neuro brain CORE - Sheet1 Flashcards
baby brain myelination: which changes first, T1 or T2
T1 changes precede the T2 changes (adult T1 pattern seen around age 1 , adult T2 pattern seen around age 2).
last part of the brain to myelinate?
subcortical white matter (inf–>sup, central–>peripheral, sensory–>motor)
which way does the corpus callosum form?
front to back (then rostrum last)
MRI signal of skull bone marrow in babies
T1 hypointense in young kids, fatty in older kids (T1 bright)
order of sinus formation
maxillary, ethmoid, sphenoid, frontal
normal change in globus pallidus with age
brain iron increases, GP darkens up
imprint of the high heeled shoe
oval part = foramen ovale, pointy heel = foramen spinosum
foramen rotundum on the different views
axial = point heel of high-heeled shoe, sag = “level” (totally horizontal), coronal = coming straight at you
what CN runs next to the carotid in the cavernous sinus?
CN6 (you get lateral rectus palsy earlier with cav sinus pathology)
branches of the external carotid
superior thyroid, ascending pharyngeal, lingual, facial, occipital, post auricular, maxillary, superficial temporal (Some Admins Like Fucking Over Poor Medical Students)
number of the carotids
C1 (cervical), C2 (petrous), C3 (lacerum), C4 (cavernous), C5 (clinoid), C6 (ophthalmic/supraclinoid), C7 (communication/terminal)
persistent fetal connection between cavernous ICA (C4) and basilar artery?
persistent trigeminal artery (increases risk of aneurysm)
what’s it called when the carotid artery courses through the tympanic cavity to join the horizontal carotid canal?
aberrant carotid artery - pulsatile! don’t biopsy
3 deep cerebral veins
basal vein of rosenthal, vein of galen, inferior petrosal sinus
superior and inferior anastomic veins ( collateral veins for alternate superficial middle cerebral vein) are also called
Trolard (top) and Labbe (lower)
If I say “CN 3 palsy”, you say
PCOM aneursym
If I say “CN 6 palsy”, you say
increased ICP
classic findings in intracranial hypotension
- dural enhancement 2. distension of dural venous sinuses 3. prominence of intracranial vessels 4. engorgement of pituitary 5. subdural hematoma/hygromas
classic findings in intracranial hypertension (pseudotumor)
- slit like vents 2. partially empty sella 3. compressed venous sinuses 4. tortuous optic nerves 5. flattening of posterior sclera
most common congenital obstructive hydrocephalus
aqueductal stenosis (usually from a web or diaphragm)
pathophys of communicating hydrocephalus
obstruction at the level of the villi/granulation, blocking reabsorption (all vents will be dilated)
4 causes of communicating hydrocephalus
- NPH 2. SAH 3. Meningitis 4. Carcinomatous meningitis
pathophys of non-obstructive hydrocephalus
something that produces CSF (choroid plexus papilloma)
don’t be silly, if you see transependymal flow, is the hydrocephalus acute or chronic?
acute dummy
another name for subfalcine herniation
midline shift (ACA can get compressed)
what kind of vascular injury can you get with descending transtenorial herniation?
Duret Hemorrhages - compression of perforating basilar artery branches, seen at midline of pontomesencephalic junction
what CN injury can you get with descending transtenorial herniation?
CN3 gets compressed between the PCA and Superior Cerebellar Artery causing ipsilateral pupil dilation and ptosis
when do we see Ascending transtentorial herniation?
posterior fossa mass - causes severe obstructive hydro
fulminant form of ADEM with massive brain swelling and death
acute hemorrhagic leukoencephalitis (Hurst)
neuromyelitis optica aka
Devics (transverse myelitis + optic neuritis)
MS variant in kids that is horrible
Marburg Variant - fulminant, leads to rapid death, may have febrile prodrome
classic findings in Wernicke encephalopathy
- enhancement of the mammillary bodies 2. T2/FLAIR in bilateral medial thalamus and periaqueductal gray
defiency in Wernicke
thiamine
classic findings in CO poisoning
CT hypodensity/T2 bright globus pallidus (CO causes “globus warming”
Marchiafava-Bignami: findings
Swelling and T2 bright signal affecting the corpus callosum
classic findings in methanol toxicity
Optic nerve atrophy, hemorrhagic putamina! and subcortical white matter necrosis
On PET, what is always preserved in dementia?
the motor strip
Binswanger disease is a form of what kind of dementia
small vessel vascular dementia - seen in older ppl with HTN, spares the subcortical U fibers
dementia classic findings on PET: alzheimer
low posterior temporoparietal cortical activity
dementia classic findings on PET: multi-infarct
scattered areas of decreased activity
dementia classic findings on PET: Lewy bodies
low in lateral occipital cortex (sparing cingular gyrus)
dementia classic findings on PET: Picks/frontotemporal
low frontal lobe (depression is a mimic)
dementia classic findings on PET: huntington
low activity in caudate and putamen
TORCH findings: CMV
Most Common, Periventricular Calcifications, Polymicrogyria
TORCH findings: toxo
Hydrocephalus, Basal Ganglia Calcifications
TORCH findings: rubella
Vasculopathy/ischemia. High T2 signal- Less Calcifications
TORCH findings: HSV
Hemorrhagic Infarct, and lead to bad encephalomalcia (hydranencephaly)
TORCH findings: HIV
Brain Atrophy in frontal lobes
HIV infections: AIDS encephalitis
symmetric T2 bright, spares U fibers
HIV infections: PML
asymmetric T2 bright (out of proportion to mass effect), involved U fibers
HIV infections: CMV
periventricular T2 bright, ependymal enhancement, brain atrophy
HIV infections: toxo
ring enhancement with LOTS of edema
HIV infections: cryptococcus
dilated perivascular spaces filled with mucoid gelatinous crap, basilar meningitis
HSV 1 or 2 in adults vs. babies
HSV 1 in adults, HSV 2 in babies
what sequence is most sensitive in HSV encephalitis?
diffusion is more sensitive than T2
looks like HSV encephalitis, but HSV titer negative
limbic encephalitis - paraneoplastic from small cell lung ca - ask for lung cancer screening
infection that involves the basal ganglia?
West Nile - T2 bright basal ganglia and thalamus, with restricted diffusion.
3 ways to show CJD
- cortical gyriform restricted diffusion 2. restricted diffusion in medial thalamus (hockey stick sign) 3. series of MR/CTs showing rapidly progressive atrophy
4 stages of neurocysticercosis
- Vesicular- thin walled cyst (iso-iso TI/T2 + no edema) 2. Colloidal - hyperdense cyst (bright-bright T I /T2 + edema) 3. Granular - cyst shrinks, wall thickens (less edema) 4. Nodular -small calcified lesion (no edema)
5 supratentorial peds tumors
- astrocytoma 2. PXA 3. PNET 4. DNET 5. ganglioglioma
4 infratentorial peds tumors
- JPA 2. medulloblastoma 3. ependymoma 4. brainstem astrocytoma
3 supratentorial adult tumors
- mets ++ 2. astrocytoma 3. oligodendroglioma
2 infratentotial adult tumors
- JPA 2. hemangioblastoma
4 CP angle tumors
- schwannoma 2. meningioma 3. epidermoid 4. arachnoic cyst
3 cortically based tumors
DOG - 1. DNET 2. oligodendroglioma 3. ganglioglioma
3 tumors that like to be multifocal
- lymphoma 2. multicentric GBM 3. gliomatosis cerebri
4 tumors that are multifocal from seeding
- medulloblastoma 2. ependymoma 3. GBM 4. oligodendroglioma