Neuro Flashcards
Order of myelination
- inferior to superior
- posterior to anterior
- central to peripheral
- sensory then motor
last structures to myelinate
subcortical white matter (occipital at 12 months, frontal at 18 months)
structures that are myelinated at birth
- posterior limb of internal capsule
- brainstem
order of sinus formation
maxillary –> ethmoid –> sphenoid –> Frontal
what structures are in the superior orbital fissure
CN 3, CN4 ,CN V1, CN6
what structures are in the inferior orbital fissure
V2
Segments of the ICA
C1: cervical
C2: petrous:
C3: Lacerum
C4: cavernous
C5: clinoid - aneurysm can compress CN2
C6: Supraclinoid (Ophthalmic) - common site for aneurysm; originats at dural ring
C7: communicating/terminal - aneurysm can compress CN3
What structure can get compressed with a subfalcine herniation
C
What are signs of an uncal herniation
aka descending transtentorial
- ipsilateral hemiparesis (Kernohan’s notch phenomenon)
- ipsilateral pupillary dilation and ptosis from CN3 compression
Marchiafava Bignami
- alcoholics
- edema and T2 bright in corpus callosum (beginning in body, then genu, then splenium); affects central fibers and spares the dorsal and ventral fibers (sandwich sign)
disseminated necrotizing leukoencephalopathy
- seen in leukemia patients getting radiation and chemo
- severe white matter changes, with ring enhancement
- can be fatal
Subcortical Arteriosclerotic Encephalopathy
- aka Binswanger disease
- multi-infarct dementia that only involves white matter
- favors white matter of centrum semiovale
- spares subcortical U fibers
- strong association with HTN
- older patients 55+
CADASIL
Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy
- 40 year old with migraines
- severe white matter disease involving multiple vascular territories in frontal and temporal lobes
- occipital lobes are usually spared
Primary brain tumors that can be multifocal
- lymphoma
- GBM - can be multicentric or can be multiple from seeding
- gliomatosis cerebri
- Medulloblastoma (from seeding)
- ependymoma (From seeding)
- Oligodendroglioma (From seeding
Cortically based tumors
PDOG
- pleomorphic Xanthoastrocytoma
- Dysembryoplastic Neuroepithelial tumor (DNET)
- Oligodendrogliomas
- Gangliogliomas
Pleomorphic Xanthroastrocytoma (PXA)
- ALWAYS supratentorial
- usually involves temporal lobe
- often a cyst with a nodule
- tumor frequently invades leptomeninges
- looks similar to DIG but does not occur in an infant
- occurs at age 10-20
- enhances
DNET (Dysembroplastic Neuroepitheilal Tumor)
- kid (<20 yrs) with drug-resistant seizures
- temporal lobe
- focal cortical dysplasia seen in 80%
- little surrrounding edema
- Bubbly lesion; high T2 signal
- does NOT enhance
Oligodendroglioma
- most common in frontal lobe
- calcifies 90%
- expands the cortex
- 1p/19 q deletion - better outcome
- seen in adults (40-50s)
Ganglioglioma
- low grade; can enhance
- can occur at any age
- usually temporal lobe
- cystic and solid mass with focal calcification
Intraventricular tumors - arising from ventricular wall and septum
- ependymoma (kids)
- Medulloblastoma (in kids)
- Subependymal giant cell astrocytoma
- subependymoma (in adults)
- central neurocytoma
intraventricular tumors - arising from choroid plexus
- choroid plexus papilloma
- choroid plexus carcinoma
- xanthogranuloma
What syndromes are associated with medulloblastomas?
- Basal cell nevus
- Turcot’s syndrome
- Gorlin syndrome
Gorlin syndrome
- medulloblastoma
- dural calcification
- basal skin cancer after radiation
- odontogenic cysts
most common intraventricular mass in an adult 20-40 years old
central neurocystoma
Cerebellopontine angle masses
schwannoma (75%)
menignioma
epidermoid
Infratentorial tumors
- AT/RT
- medulloblastoma
- ependymoma
- JPA
- Hemangioblastoma
- ganglioglioma
- Diffuse Pontine glioma
Supratentorial tumors
- Mets
- Astrocytoma
- Gliomatosis cerebri
- oligodendroglioma
- primary CNS lymphoma
hemangiopericytoma
soft tissue sarcoma that can mimic an aggressive meningioma because both enhance homogeneously
- will not calcify or cause hyperostosis
- will invade the skull
signal of blood on MRI
- hyperacute (<24 hours): T1 iso, T2 bright
- acute (1-3 days): T1 iso, T2 dark
- early subacute (3-7 days): T1 bright, T2 dark)
- late subacute (7-14 days): T1 bright, T2 bright)
- chronic (> 14 days): T1 dark, T2 dark)
most sensitive sequence for subarachnoid hemorrhage
FLAIR
Iniencephaly
star gazing fetus: upturned face, hypextended C-spine, short neck
- deficit of occipital bones, resulting in an enlarged foramen magnum
Joubert syndrome associations
- elongated superior cerebellar peduncles
- small or aplastic vermis
- absence of pyramdial decussation
- strong assocaition with retinal dysplasia
- association with multicystic dysplastic kidney
Meckel Gruber syndrome
- occipital encephalocele
- multiple renal cysts
- polydactyly
- strong association with holoprosencephaly
Associations with holoprosencephaly
- single midline monster eye
- solitary median maxillary incisor
- pyriform aperture stenosis (From nasal process overgrowth)
schizencephaly associations
- optic nerve hypoplasia
- absent septum pellucidum
- epilepsy
Chiari 1 malformation association
Klippel Feil syndrome
Apert’s
brachycephaly + fused fingers
Crouzon’s
brachycephaly + first arch (maxilla and mandible) hypoplasia
Cleidocranial dysostosis
brachycephaly + wormian bones + absent clavicles
MELAS
mitochondrial encephalomyopathy, lactic acidosis, and stroke like episodes
on MR spectroscopy: increased lactate; decreased NAA
most common leukodystrophy? what does it look like?
Metachromatic
- diffuse white matter involvement with tigroid apperance
High NAA peak
Canavan’s disease
TE needed to invert the lactate peak
intermediate TE (140) at long TE (280) - lipid and lactate double peak seen
elevated myoinositol peak
Alzheimer’s disease
elevated alanine peak
meningiomas
elevated glutamine
hepatic encephalopathy
high grade tumor: what does the MRS look like?
- elevated choline, lactate, and lipids
- decreased NAA
low grade tumor: what does the MRS look like?
- decreased choline, NAA
- elevated inositol
MRS in radiation necrosis
- decreased choline and NAA
- increased lactate
Gradenigo syndrome
complication of Apical petrositis, when Dorello's canal is involved triad of: 1) otomastoiditis 2) facial pain (trigeminal neuropathy) 3) lateral rectus palsy (CN 6)
what is the main blood supply to the posterior nose
sphenopalatine artery (terminal internal maxillary artery)
most common masticator space “Mass”
odontogenic abscess
order of muscle involvement in Grave’s orbitopathy
inferior rectus –> Medial rectus –> superior rectus –> lateral rectus –> superior/inferior obliques (IM SLO)
ACR recommendations prior to lumbar puncture (regarding anticoagulation)
- stop Plavix 7 days prior
- stop coumadin 4-5 days prior
- stop LMW heparin 24 hours prio
- hold heparin for 2-4 hours and document normal PTT
- ASA and NSAIDS are fine
Currarino triad
- sacrococcygeal osseous defect (scimitar sacrum)
- anorectal malformation
- anterior sacral meningocele
Foix Alajouanine syndrome
myelopathy associated with a dural VF
