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What are the most common causes of subarachnoid hemorrhage?
Rupture of aneurysm
What is the pathophysiology of subdural hematoma?
- Deceleration/acceleration forces
- Tear bridging veins
What vessels are damaged in epidural hematomas?
Damage to middle meningeal artery
Hemorrhage at grey-white junction
What is the most common cause of intracerebral hemorrhage?
What vessels are involved in hypertensive hemorrhage?
Deep penetrating arteries
Where do cerebral artery aneurysms tend to occur?
Branch points of intracranial vessels
What are structures that can be affected by acute stroke?
Obscuration of lentiform nuclei
Loss of insular ribbon
Why are the lentiform nuclei obscured in acute stroke?
Proximal MCA occlusion leading to limited flow to the lenticulostriate arteries
Concha bullosa - pneumatization of the middle turbinate
What is concha bullosa associated with?
Nasal septal deviation
Haller cell - Infraorbital ethmoid air cell
What is the most common intracranial abnormality in battered children?
Where do traumatic subdural hematomas tend to occur?
What separates the frontal and parietal lobes?
Central (Rolandic) sulcus
What regions in the brain regions affected by MS?
- 1. Periventricular
- 2. Spinal cord
- 3. Juxtacortical (touching cortex)
- 4. Infratentorial
What is the difference between focal and broad based herniation?
Focal herniation - less than 90 degrees of disc circumference
Broadbased herniation - anywhere between 90-180 degrees
What is the difference between migration and sequestration?
Migration - displaced disc material away from site of extrusion
Sequestration - displaced disc material has lost connection with the parent disc
What is the order of involvement of the extraocular muscles in thyroid eye disease?
- I - inferior rectus
- M - medial rectur
- S - superior rectus
- L - lateral rectus
- O - obliques
What are the most common intramedullary, intradural tumors?
What are the different types of nerve sheath tumors?
What findings are associated with neurofibromatosis II?
- M - Multiple
- I - Inherited
- S - Schwannomas
- M - Meningiomas
- E - Ependymomas
What syndrome is associated with multiple neurofibromas?
Neurofibromatosis Type I
What additional findings in a peripheral nerve sheath tumor that go along with Neurofibromatosis Type I?
Ribbon ribs (rib dysplasia)
Scalloping of the posterior vertebral body (dural ectasia)
What is the most common tumor associated with chronic temporal lobe epilepsy?
What is the most common central cause of precocious puberty?
What are the most common tumors of the optic nerve?
Glioma (most common)
Meningiomas grow in linear fashion along optic nerve
"Tram track" - pattern of enhancement of sheath
May also be extensive calcified
What syndrome are optic nerve gliomas associated with?
Neurofibromatosis Type I
How can one distinguish ependymomas from astrocytomas in the spinal cord?
Astrocytomas - longer segment of cord involvement
More likely to be infiltrative
LESS LIKELY - hemorrhage or tumor cyst
What is the pathophysiology of Sturge Weber syndrome?
Fetal cortical veins fail to develop normally
Leads to chronic venous ischemia
Sturge Weber Syndrome
Cortical "tram track" calcification
Atrophy of affected side (side with port wine stain)
Enlarged ipsilateral choroid plexus
What is cranial nerves are most commonly affected by schwannomas?
Cranial nerve VIII (eight is most common)
Cranial nerve V
What is the differential diagnosis for mass type lesions that cross midline?
Vermian hypogenesis leading to "molar tooth" appearance of 4th ventricle and superior cerebellar peduncles
What is the definition of holoprosencephaly?
Failure of cleavage of prosencephalon into telencephalon and diencephalon
What are the most and least severe forms of holoprosencephaly?
Alobar - most severe form
Semilobar - in between
Lobar - least severe form
What are the two major types of cholesteatomas?
Pars flaccida (80%)
Pars tensa (15%)
What is the most common tumor of the middle ear?
Glomus tympanicum paraganglioma
Vertebra plana (pancake vertebral body)
Sparing of disc space
What are characteristic imaging and clinical findings of carotid cavernous fistula?
Dilation of superior opthalmic vein
What is the most common tumor in the lateral ventricle of a child?
Choroid plexus papilloma
What part of the lateral ventricles are affected first in hydrocephalus?
How can one distinguish hydrancephaly versus hydrocephalus?
Hydrocephalus - always mantle of brain parenchyma
What are the TORCH infections?
- T - toxoplasmosis
- O - Other (varicella)
- R - Rubella
- C - cytomegalovirus (CMV)H - Herpes simplex
What infection is suspected in the setting of a normal size head and intracranial calcifications (parenchymal, not periventricular)?
What are the two types of cephaloceles?
Meningocele - protrusion of meninges through calvarial defect
Encephalocele - protrusion of brain tissue through calvarial defect
What is the difference between a sulcus and gyrus?
Sulcus - depression/fissure in surface of brain
Gyrus - gyri are surrounded by sulci (depressions)
What are the stages of development of the cerebral cortex?
What disorders result from abnormalities of neuronal cell proliferation?
Too many cells - hemimegancephaly
Too few cells - microlissencephaly/microcephaly
How can one distinguish epidermoid cysts from arachnoid cysts on diffusion weighted imaging?
Epidermoid cysts - keratin material restricts free diffusion of water
Arachnoid cysts - no restriction of diffusion of water
What are the parts of the corpus callosum?
Genu - anterior
Splenium - posterior
How does CSF flow from the ventricular system?
Lateral ventricles > Foramen of Monro > Third ventricle > Cerebral aqueduct (Aqueduct of sylvius) > Fourth ventricle > Foramen of Magendie/Luschka
How do brain metastases present in children versus adults?
Children - leptomeningeal spread
Adults - gray-white junction
What is the expected spectroscopy profile of glioblastoma?
What is the one pathologic condition that does not manifest in low NAA (and high choline)?
Canavan disease- markedly elevated NAA level
What is a cholesterol granuloma?
Granulation tissue in the middle ear
What is a cholesteatoma histologically?
What are the major types of cholesteatomas and how often do they occur?
What is choanal atresia?
Block of back of nasal passage due to bone or membrane
What syndrome are angiomyolipomas associated with?
Enhancing cribiform plate mass with cysts at tumor/brain margin
What is the white matter above the ventricles called?
- Corona radiata
Creutzfeldt Jacob disease
- T2 hyperintensity/restricted diffusion
- - Caudate
- - Putamen
- - Thalamus (hockey stick)
- - Cortex
What space is used to determine the location of masses in the suprahyoid space?
Balo concentric sclerosis
Variant of MS - alternating bands of demyelinated white matter
- Bilateral thalamic infarcts - internal cerebral vein thrombosis (straight sinus, vein of Galen)
Venous infarcts - often bilateral, midline and hemorrhagic
Bilateral thalamic and midbrain infarcts -
Artery of Percheron infarct
- Single arterial trunk coming off PCA supplying portion of thalamus and midbrain
3 year old boy with seizures
Most common location in subarachnoid space
- Atlanto-occipital dissociation - basion dens interval is greater than 12 mm
What are the two most common odontogenic tumors?
Odontoma ("tooth hamartomas")
Young male presenting with muscle spasms and seizures
X-linked adrenoleukodystrophy - genetic defect in paroxysmal oxidation of fatty acids
Posterior periventricular white matter changes
Can get areas of enhancement (not seen in metachromatic leukodystrophy)
What is the MOST common hereditary leukodystrophy?
Indentation of the frontal bones (typically seen before 24 weeks)
- Associated with:
- Spina bifida
- Chiari II Malformation
11 year old with history of dystonia
Pantothenate kinase degeneration (previously known as Hallervorden-Spatz syndrome) - excess iron accumulation in globus pallidi
Low signal intensity of globus pallidi surrounding central small hyperintense area
Dysmelinating disease - "Tigroid" appearance of white matter