1
Q
patterns of PRES
A
- parieto-occipital lobes
- holohemispheric at watershed zones
- superior frontal sulcus
2
Q
difference between porencephaly & schizencephaly
A
- porencephalic cyst CSF filled lined with reactive gliosis
2. schizencephaly lined by grey matter
3
Q
carbon monoxide poisoning
A
bilat globi pallidi necrosis
4
Q
what lines virchow-robin spaces
A
pia
5
Q
HIV encephalitis
A
- progressive atrophy and symmetric, periventricular or diffuse patchy/confluent white matter disease
- characteristic sparing of the subcortical-U fibers
6
Q
cribriform plate is in the superior aspect of what bone?
A
ethmoid
7
Q
which show restricted diffusion?
medulloblastoma, ATRT, ependymoma
A
medulloblastoma
ATRT
8
Q
contents of meckels cave
A
CSF (90%)
fascicles CN V
trigeminal/semilunar/Gasserian ganglion
(posterolateral to cavernous sinus)
9
Q
only nerve to exit dorsal brainstem
A
CN IV
trochlear
10
Q
tram track calcification along optic nerve
A
optic n meningioma
11
Q
recurrent laryngeal nerve sits in here bilaterally
A
tracheoesophageal groove
12
Q
bilat vestibular schwannomas
A
NF2
13
Q
NF2 mutation
A
22q12
14
Q
artery of percheron infarct
A
central midbrain
medial thalami
15
Q
NF 1 mutation
A
17q11.2
auto dom
100% penetrance
16
Q
antibody in neuromyelitis optica
A
anti NMO IgG
against aquaporin 4
17
Q
CN nuclei in the medulla
A
CN 9, 10, 11, 12
18
Q
CN 7 nuclei
A
mid pons
19
Q
normal T1 signal vertebral bodies
A
brighter than disc
20
Q
stages of neurocysticercosis
A
- Vesicular (viable larva): small 10mm cysts w scolex, follows CSF, no edema
- Colloidal (dying larva): inflammation, hyperintense to CSF, enhancement, surrounding edema
- Granular nodular (healing): cyst involutes, wall thickens, edema ↓
- Nodular calcified (healed): no edema, MR black dots
21
Q
cause of neurocysticercosis
A
taenia solium
22
Q
findings of NFI
A
‘substance’
- waxing/waning WM lesions (UBO, FASI)
- optic n glioma
- optic pathway glioma
- brain gliomas (brainstem, cerebral, basal ganglia)
- [plexiform] neurofibroma
- vascular dysplasia
- cafe au lait spots
- dysplastic skeletal lesions
23
Q
findings of NFII
A
‘layers’
- multiple CN schwannomas
- meningiomas
- spinal tumors/ependymomas
MISME - multiple inherited schwannomas meningiomas and ependymomas
24
Q
clinical criteria of NFI
A
2+ of:
≥ 6 café au lait spots ≥ 15 mm adults or 5 mm children
≥ 2 neurofibromas or 1 plexiform neurofibroma
Axillary/inguinal freckling
Visual pathway glioma
≥ 2 iris hamartomas (“Lisch nodules”)
Distinctive bony lesion (sphenoid wing dysplasia, thinning of long bone ± pseudoarthrosis)
1st-degree relative with NF1
25
% inverted sinonasal papilloma convert to/coexist w/ SCCa
10%
26
gene affected in NFIII (schwannomatosis)
SMARCB1
27
length of MS spinal lesions
usually <2 vert bodies
28
length of transverse myelitis lesions
usually >2 vert bodies
29
most common intramedullary neoplasm in adults
ependymoma
30
second most common intramedullary neoplasm in adults
astrocytoma
31
most common intramedullary spinal neoplasm in kids
astrocytoma
32
length of NMO lesions
usually >3 vert bodies
33
criteria for NMO (Devic)
2/3 of:
- Contiguous cord lesion 3 or more segments in length
- initial brain MR nondiagnostic for MS
- NMO-IgG seropositivity
34
cannot distinguish NMO from this if optic neuritis and myelitis on 1st scan:
ADEM - acute disseminated encephalomyelitis
35
mutation in CADASIL
NOTCH3 - chromosome 19
36
stroke in middle aged, healthy adults
think CADASIL
37
classic triad susac syndrome
Encephalopathy
Branch retinal artery occlusions
Hearing loss
38
most common meningitis bugs
- strep pneumo
- n meningitidis
- haemophilus influenzae
39
most common CNS fungal infection
cryptococcosis
40
most common CNS infection worldwide
cysticercosis
41
most common tumor in chronic temporal lobe epilepsy
ganglioglioma
42
association with dysplastic cerebellar gangliocytoma (lhermitte-duclos disease)
cowden syndrome
| 10q23
43
#1 CNS neoplasm in tuberous sclerosis
subependymal giant cell astrocytoma
44
most common tumor in cauda equina region
myxopapillary ependymoma
45
glomus tympanicum paraganglioma vs glomus jugulare --> floor in tact vs destroyed
in tact = tympanicum; destroyed = jugulare
46
only CN withIN the cavernous sinus
CN6 abducens
47
'cold' spondylodiscitis causes
Tb
| Brucella
48
rhomboencephalitis involves what
hindbrain = cerebellum and brainstem
49
bacteria in lemierre's
Fusobacterium necrophorum
50
gradenigo syndrome triad & cause
1. otitis media
2. periorbital pain (CN V)
3. abducens palsy (CN VI)
cause: petrous apicitis
51
association of T2 FLAIR mismatch
highly specific for IDH-mutated 1p/19q non-codeleted astrocytoma
(vs other lower grade gliomas, oligodendroglioma)
52
most common met to parasellar region
breast ca
53
syndrome caused by compression of tectal plate
parinaud syndrome
- upward gaze paralysis
- pupillary light dissociation
- nystagmus
54
central Ca2+ pineal gland
| exploded Ca2+ pineal gland
- germinoma
| - pineoblastoma
55
#1 extraaxial hematoma
traumatic SAH
56
#2 extraaxial hematoma
acute subdural
57
terson syndrome
intraocular hemorrhage with SAH
58
recurrent artery of Heubner supplies...
- head and anteromedial caudate nucleus
| - anterior limb internal capsule
59
medial lenticulostriate arise from?
| lateral?
A1
| MCA
60
calcifications of pineoblastoma and germinoma
blastoma blasts apart the Ca2+
| germinoma enGulfs the Ca2+
61
causes of convexal SAH (#10)
- dural sinus and cortical vein thrombosis
- arteriovenous malformations
- dural arteriovenous fistulas
- arterial dissection/stenosis/occlusion
- mycotic aneurysm
- vasculitides
- amyloid angiopathy
- coagulopathies
- RCVS
- posterior reversible encephalopathy syndrome
62
inheritance of sturge weber
sporadic
63
path of CN 6 (abducens)
- front of pons (medial to 5)
- up durrelos canal (clivus)
- through cavernous sinus
- up through superior orbital fissure
- orbit
- lateral rectus
64
brain tumor classically Ca2+
oligodendroglioma
65
cerebrovascular malformations w/ arteriovenous shunt
- AVM
- dural AV fistula
- vein of galen malformation
66
wyburn mason syndrome
AVMs of retina and brain
67
optic canal contents
optic nerve CNII
| ophthalmic artery
68
superior orbital fissure contents
```
CN III
CN IV
CN V1
CN VI
sup'r and inf'r ophthalmic veins
```
69
longest cranial nerve
CN IV - trochlear
| posterior decussation
70
Marchiafava-Bignami disease
rare, alcoholics
osmotic demyelination & necrosis of corpus callosum central fibers (sandwich sign on sagittal)
FLAIR hyperintense, nonenhancing T1 hypointense
71
Dandy Walker malformation
- large posterior fossa
- cyst extending posteriorly from 4th ventricle
- vermian agenesis/hypoplasia
- torcular-lambdoid inversion
72
Ramsay Hunt syndrome
shingles/herpes zoster of facial n
- VZV reactivation in geniculate ganglion
- triad: ear pain, facial paralysis, painful vesicular eruption involving EAC, pinna, tongue or hard palate
73
oxyhemoglobin: time, RBC, T1 and T2 signal
hyperacute (<1 day)
RBC intact
T1 iso
T2 bright
74
deoxyhemoglobin: time, RBC, T1 and T2 signal
acute (1-3 days)
RBC intact
T1 iso
T2 dark
75
methemoglobin (intracellular): time, RBC, T1 and T2 signal
early subacute (3-7 days)
RBC intact
T1 bright
T2 dark
76
methemoglobin (extracellular): time, RBC, T1 and T2 signal
late subacute (7 to 14-28 days)
RBC lysed
T1 bright
T2 bright
77
hemosiderin: time, RBC, T1 and T2 signal
chronic (>14-28 days)
RBC lysed
T1 dark
T2 dark
78
ecchordosis physaliphora
ectopic notochord remnant
anywhere from dorsum sella to sacrum
Aunt Minnie: clival defect/cystic lesion with sclerotic margins
79
Tornwaldt cyst
- benign midline nasopharynx mucosal cyst
- high T2 signal
- notochordal remnant
80
Wallenberg/lateral medullary syndrome
occlusion of intracranial VA and/or PICA -> infarct of lateral medulla
- dysphagia (nucleus ambiguus), dysarthria, dysphonia
- ipsilat loss of pain in face
- contralat loss of pain & temp in body
+/- ataxia
81
embryonic carotid-basilar anastomoses
- persistent trigeminal artery (btwn cavernous ICA and basilar artery; Neptune’s trident)
- persistent hypoglossal artery (btwn prox cervical ICA at ~C1-2 level and BA; courses along CN XII through hypoglossal canal)
- persistent otic artery (rare)
- proatlantal/intersegmental artery (rare)
82
persistent stapedial artery - embryology, course
- stapedial a transiently present in N fetal devel, connecting branches of future ECA to ICA
- arises from C2/petrous ICA
- pass thru stapes footplate, doubles size of anterior/tympanic seg of facial n
- intracranially becomes middle meningeal artery
- assoc w aberrant ICA
83
persistent stapedial artery - CT findings
- absence of foramen spinosum
| - enlarged tympanic seg of facial n (contains soft tissue)
84
aberrant ICA - course, clinical
- laterally displaced ICA
- enters posterior middle ear cavity from below and hugs cochlear promontory as it crosses middle ear cavity
- then resumes N expected course as it joins post-lat margin of horizontal petrous ICA
- pulsatile tinnitus, vascular retrotympanic mass in anteroinferior mesotympanum
- mimics glomus tympanicum
- assoc w persistent stapedial a
85
aberrant ICA - imaging CT & angio
CT:
- tubular lesion crossing middle ear cavity from posterior to anterior
- soft tissue density lying on cochlear promontory
Angio:
- angulation resembling a 7, change in contour and caliber (pinched appearance)
86
CADASIL - imaging
- symmetric high T2 subcortical WM
- anterior temporal lobes + external capsules
+ lacunar infarcts
87
CADASIL - clinical
recurrent stroke/TIA + migraine -> premature dementia
| young adult
88
reversible cerebral vasoconstriction syndrome
multifocal segmental arterial constrictions
- multiple vascular territories
- beaded appearance
high res wall imaging: +/- thickened wall, reduced lumen; no/minimal enhancement
convexal SAH, strokes
89
moyamoya - imaging
progressive stenosis of distal (supraclinoid) ICA and proximal CoW, eventual occlusion
anterior > posterior circulation
enlarged/innumerable basal perforating arteries, lenticulostriate collaterals
puff of smoke
children stroke, adults bleed
90
ivy sign in moyamoya
tubular branching FLAIR hyperintensities within sulci
represent cortical arterial branches that appear FLAIR hyperintense d/t slow collateral flow
+ vivid contrast enhancement
91
age of esthesioneuroblastoma (olfactory neuroblastoma)
>50
92
most common benign orbit lesion adult
hemangioma
93
most common suture to close prematurely
sagittal
94
Prussak space boundaries
lateral: pars flaccida & scutum
superior: lateral malleal ligament
medial: neck of malleus
(subcomponent of the lateral epitympanic space)
95
nuc med imaging for esthesioneuroblastoma
- neuroendocrine tumor --> somatostatin receptor
- octreotide
- MIBG
- DOTATATE
96
Spetzler Martin scale for AVMs
predicts surgical morbidity/mortality
ranges from 1-5 pts:
- size: <3cm (1), 3-6cm (2), >6cm (3)
- location: noneloquent (0), eloquent area of brain (1)
- venous drainage: superficial (0), deep (1)
97
triangle of Guillain & Mollaret
dentatorubro-olivary pathway:
- contralateral dentate nucleus (lateral cerebellar nuclei)
- red nucleus (tegmentum of midbrain)
- inferior olivary nucleus (medulla)
damaged in hypertrophic olivary degeneration
98
hypertrophic olivary degeneration
hypertrophied & T2 hyperintense inferior olivary nucleus with a causative lesion in the brainstem:
- infarct, hemorrhage, demyelination, surgery
damage to triangle of Guillain & Mollaret
99
dysembyroplastic neuroepithelial tumor
"bubbly" lesion without mass effect
cortically based
wedge shaped
multilobulated
young pt with longstanding hx of seizures
100
mesial temporal sclerosis imaging findings
reduced hippocampal volume
increased T2 signal (gliosis, scar)
loss of normal interdigitations
late:
atrophy of ipsilateral fornix & mammillary body
101
Wernicke's encephalopathy: affected areas
mammillary bodies
dorsomedial thalami
periaqueductal grey matter
tectal plate
102
nonketotic hyperglycemia with hemichorea-hemiballismus: imaging appearance
hyperdense (CT) and T1 hyperintense basal ganglia (esp putamen) contralateral to side of movement disorder
normal signal on T2 & DWI
103
spinal AVM/AVF classification
type 1: dural AVF (single coiled vessel, MC: 85%)
type 2: intramedullary nidus from ant or post spinal a (+/- aneurysm, SAH; assoc w HHT, KTS)
type 3: juvenile (very rare, complex, bad prog)
type 4: intradural perimedullary (near conus, subtypes: single vs multiple arterial supply)
104
pterygopalatine fossa: 6 openings
1. inferior orbital fissure (anterosup/“roof”) → orbit
2. sphenopalatine foramen (medial) → nasopharynx via superior meatus (*origin of JNA)
3. pterygomaxillary fissure (lateral) → masticator space
4. foramen rotundum (posterosup) → middle cranial fossa
5. vidian canal (posteroinf) → directly below f. rotundum
6. greater & lesser palatine foramina (inferior/“floor”) → oral cavity
105
syndrome associated with multiple DVAs
blue rubber bleb nevus syndrome
106
genes associated with cavernomas
CCM1 (KRIT1)
CCM2 (OSM)
CCM3 (PDCD10)
107
most common cerebral vascular malformations
1. DVA
2. capillary telangiectasia
3. cavernoma
108
Sturge Weber dominant findings
- unilateral port wine stain (nevus flammeus), usually V1 trigeminal n
- ipsilateral cerebral atrophy with cortical/subcortical tram-track calc'n (d/t vascular steal phenomenon)
- choroidal angiomas (choroidal enhancement of globe)
- leptomeningeal angiomatosis (diffuse leptomeningeal enhancement ipsilateral to facial port wine stain)
(seizures, hemiparesis)
109
2 branches of C2 (ICA)
- vidian artery
- caroticotympanic artery
(can get persistent stapedial artery from here)
110
C3 (ICA) covered by what?
- trigeminal ganglion
| - no branches
111
C4 (ICA) 2 important branches
1. meningohypophyseal trunk (supply pituitary, tentorium, clival dura)
2. inferolateral trunk (supply cranial nerves and CS dura)
112
C6 (ICA) 2 important branches
1. ophthalmic artery
| 2. superior hypophyseal (supply anterior pit lobe, infundibular stalk, optic chiasm)
113
C7 (ICA) 2 important branches
1. posterior communicating artery
| 2. anterior choroidal artery
114
distal ICA passed between which two cranial nerves?
optic & oculomotor
115
absent foramen spinosum and enlarged anterior facial nerve segment = ?
persistent stapedial artery
| intracranial becomes middle meningeal artery
116
most common circle of willis variant
hypoplastic or absent posterior communicating
117
association with agenesis of corpus callosum (#6)
- gray matter heterotopia
- Chiari II malformation
- lissencephaly
- Dandy-Walker
- cytomegalovirus infection
- fetal alcohol syndrome
118
associations with schizencephaly
- septo-optic dysplasia
- corpus callosum anomalies
- grey matter heterotopia
- absent septum pellicidum
(grey matter lined cleft extending from ependyma to pita mater)
119
facial nerve segments
"I Love Going To Makeover Parties"
Intracranial/cisternal (medial to vestibulocochlear n)
Meatal/canalicular (anterosuperior IAC)
Labyrinthine (exits IAC anteriorly thru fallopian canal, reaches genu anteriorly)
Geniculate (gives off greater petrosal n)
Tympanic (geniculate ganglion to pyramidal eminence)
Mastoid (pyramidal eminence inferiorly to stylomastoid foramen, gives chorda tympani)
Parotid/Extracranial (stylomastoid foramen to division into major branches)
120
facial nerve terminal motor branches
"Tall Zulus Bear Many Children"
"To Zanzibar By Motor Car"
```
Temporal
Zygomatic
Buccal
Mandibular
Cervical
```
121
VHL findings
- multiple hemangioblastomas
- ocular angiomas
- pancreatic and renal cysts
- renal cell carcinoma
- pheochromocytoma
- cystadenomas
- islet cell tumors
- endolymphatic sac tumors
VHL tumor suppressor gene (auto dom't)
122
dorello canal
bony canal
transmits CN VI/abducens nerve
from prepontine cistern to cavernous sinus
123
superior orbital fissure contains which nerves?
CN III, IV, V1 ophthalmic, VI
"Lazy French Tarts Sit Nakedly In Anticipation" (sup to inf)
```
L: lacrimal n (branch CN V1)
F: frontal n (branch CN V1)
T: trochlear n (CN IV)
S: superior division of the oculomotor n (CN III)
N: nasociliary n (branch of CN V1)
I: inf division of oculomotor n (CN III)
A: abducens n (CN VI)
```
124
foramen rotundum contains...
CN V2 maxillary
125
foramen ovale contains...
CN V3 mandibular
| accessory meningeal artery
126
foramen spinosum contains...
middle meningeal artery & vein
| meningeal br of V3
127
inferior orbital fissure contains...
"Inferior Orbit Gets Infra-Orbital Nerves and VeinZ"
IO: inferior ophthalmic vein (tributary to both pterygoid venous plexus & cavernous sinus)
G: ganglionic branches from pterygopalatine ganglion to maxillary div. of trigeminal n.
ION: infraorbital nerve (branch CN V2)
A: infraorbital artery (branch maxillary artery)
V: infraorbital vein
Z: zygomatic nerve (branch CN V2)
128
pars nervosa contains...
CN 9 + its tympanic branch Jacobsen’s nerve
inferior petrosal sinus
(anteromedial to pars vascularis)
129
pars vascularis contains...
CN 10 + its auricular branch Arnold’s nerve
CN 11
jugular bulb
posterior meningeal br of ascending pharyngeal art
(posterolateral to pars nervosa)
130
what branches of the trigeminal nerve are in which foramen?
Standing Room Only
S: Superior orbital fissure - V1 ophthalmic
R: foramen Rotundum - V2 maxillary
O: foramen Ovale - V3 mandibular
131
mesial temporal sclerosis: hippocampus findings
volume, signal, morphology
- reduced volume/atrophy
- increased T2 signal
- abN morphology: loss of internal architecture (interdigitations of hippocampus)
132
cerebral peduncles
1 pair (vs 3 pairs of cerebellar peduncles)
- anterior part of midbrain that connects remainder of brainstem to thalami
- separated by interpeduncular cistern
- contain large white matter tracts that run to and from the cerebrum
133
cerebellar peduncles
3 pairs (vs 1 pair of cerebral peduncles)
- superior cerebellar peduncles (brachium conjunctivum): cerebellum to midbrain
- middle cerebellar peduncles (brachium pontis): cerebellum to pons
- inferior cerebellar peduncles: cerebellum to medulla
134
blood supply to superior cerebellar peduncle
superior cerebellar artery (SCA)
135
blood supply to middle cerebellar peduncle
anterior inferior cerebellar artery (AICA)
| superior cerebellar artery (SCA)
136
blood supply to inferior cerebellar peduncle
posterior inferior cerebellar artery
137
what is an infundibulum (artery)
- conical outpouching from an artery with a broad base narrowing to an apex
- must be a vessel that originates from apex (may not be visible on imaging)
- commonly at origin of PCOM from supraclinoid ICA
- no risk for rupture/SAH (vs aneurysm)
138
ICA segments (Bouthillier)
```
C1: cervical
C2: petrous (horizontal)
C3: lacerum
C4: cavernous
C5: clinoid
C6: ophthalmic (supraclinoid)
C7: communicating (terminal)
```
139
branches of petrous (horizontal) segment of ICA
- caroticotympanic artery
| - Vidian artery
140
branches of lacerum segment of ICA
none
141
branches of cavernous segment of ICA
- meningohypophyseal trunk
- inferolateral trunk
- capsular arteries (of McConnell) (variable)
142
branches of clinoid segment of ICA
none
143
branches of ophthalmic (supraclinoid) segment of ICA
- ophthalmic artery
| - superior hypophyseal artery
144
branches of communicating segment of ICA
- posterior communicating artery
- anterior choroidal artery
- anterior cerebral artery
- middle cerebral artery
145
idiopathic intracranial hypertension - findings
optic nerves: prominent SAS around CNII, vertical tortuosity/kinking, papilledema
enlarged arachnoid outpouchings: empty sella turcica, enlarged Meckel cave, prominent arachnoid granulations within temporal bone, sphenoid wing
bilateral venous sinus stenosis: junction of transverse & jugular sinuses (most important finding)
uncommon: slit-like ventricles, acquired tonsillar ectopia
146
Tolosa Hunt
granulomatous inflammatory condition involving cavernous sinus and orbital apex
- clinical dx of exclusion: painful ophthalmoplegia 2/2 to surrounding cavernous sinus inflammation
CT: asymmetrical enlargement +/- enhancement
MRI: T1 iso-hyper, T2 hyper, enhancement
147
facial nerve - typical enhancing vs nonenhancing segments
Mild enhancement of geniculate ganglion, and proximal tympanic segments
Bad enhancement: “proximal to genu, distal to SMF”
- cisternal, meatal & labyrinthine segments: surrounded by CSF, should NOT enhance
- extracranial segment: should NOT enhance
148
3 important intratemporal branches of facial nerve, top to bottom (Osborn)
greater superficial petrosal nerve
- parasymp fibers supplying lacrimal gland
stapedius nerve
- innervate stapedius muscle
chorda tympani
- taste from anterior 2/3 of tongue
149
internuclear ophthalmoplegia
disorder of conjugate gaze (ability of eyes to move in same direction at same time):
1. impaired adduction in ipsilateral eye
2. dissociated horizontal nystagmus of contralateral abducting eye
- d/t lesion in medial longitudinal fasciculus (MLF) ipsilateral to eye unable to adduct
- e.g. MS, NMO, infarct
150
CN III palsy: pupil-involving vs. pupil-sparing
pupil-involving (enlarged unreactive pupil):
- compression of CN III, because parasympathetic pupillary fibers are located peripherally in the nerve which are more likely affected by external compression
- causes: PCoA & SCA aneurysms, uncal herniation
pupil-sparing:
- cause: ischemia (microvascular infarction of the core of the nerve with relative sparing of its peripheral fibers)
151
ulegyria
shrunken cortex with flattened, mushroom-shaped gyri, d/t global hypoxic ischemic injury in term infants
centers on deepest portion of gyri, usually in parasagittal region/parietooccipital area
- it is here that perfusion is most tenuous and, therefore, most susceptible to ischemic damage
152
gelastic seizures
gelastic = laughing spells
think hypothalamic hamartoma
benign non-neoplastic heterotopias, arising from tuber cinereum
153
neuronal migrational disorders
cortical heterotopia
polymicrogyria/pachygyria
schizencephaly
lissencephaly
154
aditus ad antrum
(aka otomastoid foramen or entrance or aperture to mastoid antrum; Latin: "entrance to the cave")
def'n: the short passageway coneccting epitympanum to mastoid antrum (the large central mastoid air cell posterior to middle ear up to 1 cm)
155
Koerner septum
- thin bridge of bone dividing petrous & squamous portion of mastoid air cells at level of mastoid antrum
- serves as barrier to extension of infection from lateral to medial mastoid air cells
- commonly eroded by middle ear cholesteatomas
- important surgical landmark within mastoid air cells
156
pyramidal eminence (or process)
- small hollow anterior osseous protrusion from posterior wall of mesotympanum of petrous temporal bone
- separates sinus tympani medially from facial recess laterally
- stapedius muscle arises from the hollow of the pyramidal process, passes anterior out of apex of pyramidal eminence to attach to posterior aspect of neck of stapes
157
cochlear promontory
bone that overlies basal turn of cochlea protruding into middle ear cavity
- glomus tympanicum paragangliomas typically arise in the region of the cochlear promonotory
158
tensor tympani muscle
connects to malleus bone, pull down handle medially which tenses tympanic membrane, reducing amplitude of oscillations
supplied by nerve to medial pterygoid (branch of CNV3/mandibular n)
arises from cartilaginous part of Eustachian tube, greater wing sphenoid, petrous temporal bone;
passes into protympanum of tympanic cavity,
reflects at cochleariform process, inserts into upper end of handle of malleus
159
muscles of the temporal bone
tensor tympani muscle: stabilizes malleus
stapedius muscle: stabilizes stapes
both function to dampen sound, prevents damage to inner ear from loud sounds
160
stapedius muscle
smallest skeletal muscle in human body
stabilizes stapes (smallest bone in body)
stapedius muscle belly located in pyramidal eminence
stapedius tendon attaches to head of stapes
innervated by CNVII
161
ossicles of middle ear
malleus (anterior): umbo + manubrium + head
incus (posterior): short process, body, long process, lenticular process
stapes (medial): head, crura, footplate
162
branches of external carotid artery
```
"Some Ancient Lovers Find Old Positions More Stimulating"
"Some Angry Lady Figured Out PMS"
arising from the carotid triangle:
- superior thyroid artery
- ascending pharyngeal artery
- lingual artery
- facial artery
- occipital artery
- posterior auricular artery
```
terminal branches:
- (internal) maxillary artery
- superficial temporal artery
163
sinus tympani
clinical blind spot during standard mastoid approach to T-bone, where cholesteatomas may hide
medial wall contains: lateral SCC, tympanic segment of facial n, and oval & round windows
164
Prussak space
lateral epitympanic recess
| classic location for acquired (pars flaccida) cholesteatoma
165
5 bony parts of temporal bone
1. squamous: lat wall of middle cranial fossa
2. mastoid
3. styloid
4. tympanic: U-shaped bone, forms most of bony external ear
5. petrous: contains middle & inner ear, IAC, petrous apex
- 2 important structures anteriorly: tegmen tympani (roof of tympanic cavity) & arcuate eminence (over SCC; surgical landmark along middle cranial fossa floor)
166
round window
- 1 of 2 openings in middle ear
- basal turn of cochlea ends at round window
- communication btwn mesotympanum of middle & inner ear
- vibrates with opposite phase to vibrations from inner ear, producing movement of perilymph in cochlea
- absence or rigidity assoc w hearing loss
167
oval window
kidney-shaped aperture in medial wall of mesotympanum of middle ear
communication w vestibule of inner ear
footplate of stapes is attached to its rim by annular ligament
best visualized in coronal plane
168
epi/meso/hypotympanum
- mesotympanum (directly medial to tympanic membrane): btwn axial plane from tip of scutum to tympanic segment of facial n & axial plane from tympanic annulus to base of cochlear promontory
- epitympanum (attic): above axial plane from tip of scutum to tympanic segment of facial n
- hypotympanum: below axial plane from tympanic annulus to base of cochlear promontory
169
basal lamella (of the middle turbinate)
osseous lamella that separates anterior from posterior ethmoid sinuses
170
singular canal (aka foramen singulare, singular foramen)
thin channel within petrous temporal bone that carries singular nerve from IAC
- normal structure that may be mistaken for a temporal bone fracture
- surgical landmark during retrosigmoid approach to IAC, in which posterior wall is removed up to point of singular canal but no further to avoid fenestration of labyrinth
171
inner ear structures
bony labyrinth/otic capsule (BL) + membranous labyrinth (ML):
- BL & ML are separated by perilymph (Na+), which does not communicate w endolymph (K+) contained in membranous labyrinth
- cochlea (BL) housing cochlear duct (ML) for hearing
- vestibule (BL) housing utricle & saccule (ML) for static balance
- semicircular canals (BL) housing semicircular ducts (ML) for kinetic balance
172
Keros classification
classifies depth of recess above cribriform plate, i.e. depth of olfactory fossa
Keros I: ≤ 3 mm
Keros II: 4-7 mm
Keros III: >7 mm
173
Haller cell
cell in medial antrum, under orbital floor
next to infundibulum
may obstruct sinus drainage
174
Agger Nasi cell
most anterior ethmoid air cell
175
fovea ethmoidalis
lateral roof of ethmoid sinus
| extension of orbital plate of frontal bone
176
most common complication of functional endoscopic sinus surgery (FESS)
CSF leak
the deeper the cribriform plate with respect to fovea ethmoidalis (higher Keros), the greater chance of CSF leak
177
neck lymph node size criteria
```
long axis on axial plane
1A (submental): 0.8cm (midline)
retropharyngeal: 0.8cm
1B: 1.5cm
2A (jugulodigastric/node of Ranvier): 1.5cm
all others: 1cm
```
178
Onodi air cell
- sphenoethmoidal air cell above & lateral to sphenoid sinus
- coronal: locate air cell above sphenoid sinus and identify its continuity with a posterior ethmoid air cell
- places optic nerve at risk for intraoperative injury during posterior ethmoidectomy
179
maxillary antrum drainage
via ostiomeatal unit into MIDDLE MEATUS
(drains via maxillary ostium into infundibulum, then through hiatus semilunaris into MIDDLE MEATUS)
(best plane: coronal)
180
frontal sinus drainage
via ostiomeatal unit into MIDDLE MEATUS
(more variable than other paranasal sinuses;
frontal infundibulum -> frontal recess -> 2 main variations:
- drainage into ethmoidal infundibulum, through hiatus semilunaris into middle meatus
- drainage directly into middle meatus)
(best plane: coronal & sagittal)
181
anterior ethmoid sinus drainage
via ostiomeatal unit into MIDDLE MEATUS
(drain to hiatus semilunaris and middle meatus via ethmoid bulla, which forms parts of ostiomeatal complex)
(best plane: coronal & sagittal)
182
posterior ethmoid sinus drainage
via sphenoethmoidal recess into superior meatus
| best plane: sagittal
183
sphenoid sinus drainage
via sphenoethmoidal recess into roof of nasal cavity
| best plane: axial
184
Weber syndrome
midbrain stroke syndrome (PCA) involving cerebral peduncle & ipsilat fascicles of oculomotor n
- ipsilat CN III palsy (diplopia, ptosis, afferent pupillary defect)
- contralat hemiplegia/paresis (corticospinal/corticobulbar tracts)
- contralat parkinsonian rigidity (if substantia nigra involved)
185
nerves involved in taste
facial n: anterior 2/3 of tongue (via chorda tympani & greater superficial petrosal nerve
glossopharyngeal n: posterior 1/3 of tongue
vagus n: epiglottis region
186
hypoglossal nerve innervates what
all intrinsic and extrinsic muscles of tongue except palatoglossus muscle (vagus n)
only CN with purely motor function
187
through what structure are cochlear implants inserted?
round window
188
what is the soft tissue component of the vestibular aqueduct?
endolymphatic sac
189
what is the density in the centre of the cochlea?
modiolus
190
what does the singular canal transmit?
singular nerve
- branch of inferior vestibular nerve
- carries afferent information from posterior semicircular canal
191
trilateral retinoblastoma
pineoblastoma + bilateral retinoblastoma
192
Foix-Alajouanine syndrome
spinal dural AV fistula + progressive myelopathy
- initially: spastic paraplegia, then flaccidity, loss of sphincter control & ascending sensory level
- thought to be d/t venous hypertension
193
cavernous sinus drainage
- inferiorly through foramen ovale to pterygoid venous plexus
- posteriorly clival venous plexus, superior & inferior petrosal sinus
194
most common tumour associated with temporal lobe epilepsy
ganglioglioma
195
features ganglioglioma
50% calcify
cyst w/ enhancing nodule
can be solid
196
DNET (dysembryoplastic neuroepithelial tumor)
- bubbly
- no enhancement
- swollen gyrus
197
pleomorphic xanthroastrocytoma
- cortical/subcortical
- solid/cystic
- +/- enhancing cyst
- peritumoral edema
- +/- enhancing meningeal C+ adjacent
198
bug to cause necrotizing otitis externa
pseudomonas aeurginosa
199
etiology of and most common place of origin for plunging ranula
- Mucous retention cyst from obstructed sublingual gland/minor salivary gland
- sublingual space
200
epidermoid cyst
CSF-Iike extra-axial non-enhancing mass that is bright
| on DWl
201
arachnoid cyst
Non-enhancing unilocular extra-axial lesion
that follows CSF on all imaging modalities, including
DWl
202
epidermoid vs arachnoid cyst
both C- CSF-like but
| - epidermoid bright on DWI
203
risk factors nasopharyngeal carcinoma vs squamous cell carcinoma
1. nasopharyngeal = southern china, EBV virus
| 2. SCC = tobacco, EtOH, HPV 16
204
staging nasopharyngeal carcinoma
Tx: primary not assessed
T0: no evidence of primary but EBV+ cervical node involvement
T1: NO parapharyngeal extension (NP +/- oropharynx, nasal cavity)
T2: WITH parapharyngeal extension
T3: involve bone
T4: extension: intracranial, CN, orbit, masticator space, hypopharynx
205
```
staging HPV (-) oropharynx
(p16 negative)
```
Tx: cannot be assessed
Tis: carcinoma in situ
T1: max diameter <2 cm
T2: 2-4 cm
T3: >4 cm or to lingual surface of epiglottis
T4a (moderately advanced): involves larynx, extrinsic tongue, medial pterygoid, hard palate, mandible
T4b (very advanced): involves lateral pterygoid, pterygoid plate, lateral nasopharynx, skull base, encases carotid art
206
```
staging HPV (+) oropharynx
(p16 positive)
```
T0: not seen
T1: max diameter <2 cm
T2: 2-4 cm
T3: >4 cm or to lingual surface of epiglottis
T4: involves larynx, extrinsic tongue, medial pterygoid, hard palate, mandible or more
207
paraganglioma - most common arterial supply
ascending pharyngeal artery
208
how far down do these go:
1. retropharyngeal space
2. danger space
1. avg T3 (C7-T6)
2. diaphragm
imaging down to carina/T6 at least if ?mediastinitis
209
location of mucocele
F>E>M>S
| frontal > ethmoid > maxillary > sphenoid
210
location of conus medullaris
depends on growth of vertebral bodies
term: L2-3
3 months post-natal: L1-2
abnormal if below inferior endplate of L2
211
Brown Séquard Syndrome
decreased pain and temperature in one leg
| motor weakness on the other side
212
spinal cord herniation vs dorsal arachnoid cyst on CT myelogram
spinal cord herniation - no contrast separating it from ventral dura
dorsal arachnoid cyst - thin rim of contrast should be seen anterior to the cord
213
types of diastematomyelia
type I: 2 distinct dural sacs (bony/cartilage spur, symptomatic)
type II: 1 dural sac (fibrous spur, asymptomatic)
214
most common malignancy of thyroglossal duct cyst
papillary thyroid carcinoma
215
CT myelogram difference arachnoid cyst & neurenteric cyst
1. arachnoid POSTERIOR (dorsal)
| 2. neurenteric cyst ANTERIOR (ventral)
216
wide-neck cerebral aneurysm - definition
dome to neck ratio >2:1
| absolute cut off: >4mm neck diameter
217
pituitary stalk interruption syndrome: triad
ectopic posterior pituitary gland
thinned or absent pituitary stalk
absent or hypoplastic anterior pituitary gland
218
Modic I-III changes
Type I: T1 low, T2 high, T1C+
Type 2: T1 high, T2 iso to high
Type 3: T1 low, T2 low
219
perivascular anatomic route for nasopharyngeal carcinoma to access intracranial structures
foremen lacerum
| cartilaginous floor of anterior horizontal petrous ICA
220
perineural route of spread from masseter space to access intracranial structures occurs along...
CNV3 - mandibular
| through foramen ovale into Meckels cave and beyond
221
what is the connection between buccinator and superior pharyngeal constrictor muscles and its significance?
pterygomandibular raphe
- fibrous band extending from hamulus of medial pterygoid plate above to posterior mandibular mylohyoid line below
- lies beneath mucosa of retromolar trigone
- perifascial route of spread for retromolar trigone SCCa
222
what structure separates the lower oral cavity into the submandibular and sublingual spaces?
```
mylohyoid muscle
(except along free posterior margin)
```
223
what is the retromolar trigone?
small, triangular-shaped region of mucosa behind 3rd/last molar on mandibular ramus
- anatomical crossroads of oral cavity, oropharynx, soft palate, buccal space, floor of mouth, masticator space, and parapharyngeal space
224
parotid primary drainage site for what?
scalp
external auditory canal
deep facial structures
225
most common parotid tumor
benign mixed tumor
| aka pleomorphic adenoma
226
Earliest signal change sequences for:
- CJD
- HSV
- autoimmune encephalitis
- hypoxic ischemic injury
- hyper acute infarct
- SAH
```
CJD: DWI
HSV: DWI
Autoimmune encephalitis: FLAIR
HIE: DWI & spec (lactate, glutamine-glutamine)
Infarct: DWI
SAH: FLAIR
```
227
Most common source deep neck infection
Most common deep neck infection
Tonsilitis
Peritonsillar abscess
228
Most common facial bone fracture adult and peds
Most common orbit fracture
Adult/peds = nasal bone
Peds mandible > orbital adult
Most common orbit = inferior orbit wall
229
cranial nerve V3 (mandibular) is sensory/motor to:
```
Sensory:
- mandible (except angle)
- preauricular
- meninges
- mouth (taste via chorda tympani CN VII)
Motor:
- masticator muscles
- tensor veli palatini
- mylohyoid
- anterior belly digastric
```
230
how to confirm PML (progressive multifocal leukencephalopathy)
confirm JC virus antibody in CSF using PCR
231
Toxo vs CNS Lymphoma on nuc med & MRS
Toxo:
no uptake on SPECT or PET
lipid and lactate peaks
decreased CBV
```
Lymphoma:
uptake on SPECT or PET
decreased NAA
choline peak
+/- lipid and lactate peak
usually increased CBV
```
232
carbon monoxide poisoning vs methanol poisoning
CO: CT hypo/T2 bright globes pallidus (CO causes globus warming)
Methanol: T2 bright putaminal (May hemorrhage, CT hyper)
233
T1 bright basal ganglia
Copper and manganese deposition
- nonspecific
- related to liver disease
- TPN, Wilson’s, nonketotic hyperglycemia
234
What sequence is most sensitive for juxtacortical and periventricular plaques in MS?
Infratentorial?
Juxtacortical - FLAIR
| infratentorial - T2
235
MR spec in MS
Reduced NAA peaks in the plaques
236
First bone eroded by pars flaccida cholesteatoma
Incus (adjacent to prussaks space)
237
Retinoblastoma
Bilateral
Trilateral
Quadrilateral
Bilateral 30% of the time
Trilateral = eyes plus pineal
Quadrilateral = eyes, pineal, suprasellar
238
features parathyroid adenoma on 4D ct scan
1. NECT - hypoattenuating relative to thyroid
2. C+ art - can hyperenhance
3. C+ delayed washout
4. C+ delayed washout
239
% cavernomas with associated DVA
30%
240
white matter tracts found in agenesis of corpus callosum
bundles of probst
241
delayed radiation myelopathy
6-24 months post radiation
242
foix alajouanine syndrome
venous congestive myelopathy due to a spinal arteriovenous malformation, presenting as subacute progressive neurological deterioration. Initially, patients have a spastic paraplegia which progresses to flaccidity, loss of sphincter control, and ascending sensory level.
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