CORE - Neuro Flashcards
1
Q
Location of central sulcus relative to pars marginalis
A
central sulcus is just anterior to pars marginalis
2
Q
Innervation of “inverted omega”
A
motor function of the hand; posteriorly-directed knob arising from the precentral gyrus
3
Q
Sulci intersecting the pre-central and post-central sulci
A
superior frontal sulcus intersects the pre-central sulcus; intraparietal sulcus intersects the post-central sulcus
4
Q
Layers of cerebral cortex and hippocampus
A
6 and 3, respectively; 4 layers of cortex in lissencephaly
5
Q
Dilated Virchow-Robins spaces
A
age-related atrophy, cryptococcus, mucopolysaccharidoses; lower basal ganglia, centrum semiovale, and midbrain most commonly
6
Q
Posterior fossa mass DDx (adult)
A
hemangioblastoma, subependymoma, choroid plexus papilloma, desmoplastic medulloblastoma, mets, Lhermitte-Duclos, glioblastoma (uncommon)
7
Q
Posterior fossa mass DDx (peds)
A
ependymoma, medulloblastoma, JPA, brainstem glioma, ATRT, ganglioglioma
8
Q
Cystic space above 3rd ventricle and below fornices
A
cavum velum interpositum; extension of quadrigeminal plate cisterm to the foramen of Monro
9
Q
T1 bright substances on MRI
A
blood (met-Hgb), fat, gad, protein, mineralization, melanin, slow flow
10
Q
Fat and water content of immature myelin
A
high water, low fat => T1 dark and T2 bright white matter
11
Q
Best MR sequence(s) to assess myelination in an infant/toddler
A
T1 <6 months, T2 from 6-18 months
12
Q
Progression of myelination
A
inferior to superior, posterior to anterior, central to peripheral, sensory before motor
13
Q
Last part of brain to myelinate
A
subcortical white matter
14
Q
Normally myelinated areas at birth
A
brainstem, posterior limb of internal capsule
15
Q
Last part of corpus callosum to form
A
rostrum
16
Q
Order of paranasal sinus formation
A
maxillary => ethmoid => sphenoid => frontal
17
Q
Crossing extra-axial vessels are seen in what space?
A
subarachnoid space; if fluid collection without crossing vessels (bridging veins) => consider subdural collection
18
Q
Leptomeningeal layers
A
pia and arachnoid layers
19
Q
Absent semicircular canals
A
CHARGE syndrome
20
Q
Mondini triad
A
1.5 turns of cochlea (normal is 2.5), enlarged vestibule, enlarged vestibular aqueduct; SCCs are normal; assoc. with CHARGE
21
Q
Location of trigeminal ganglion
A
Meckel’s cave
22
Q
Contents of foramen ovale and spinosum
A
ovale contains CN V3 and accessory meningeal artery; spinosum contains middle meningeal artery
23
Q
Contents of Dorello’s canal
A
CN 6
24
Q
Contents of pars nervosa vs. pars vascularis
A
pars nervosa contains CN 9, Jacobson’s nerve, and inferior petrosal sinus; pars vascularis contains CN 10, CN 11, and jugular vein
25
Intra-temporal branches of facial nerve
chorda tympani, stapedial nerve, greater (superficial) petrosal nerve
26
Arnold's nerve
auricular branch of CN 10 (vagus n.)
27
Most medial cranial nerve in cavernous sinus
CN 6; runs along the caverous portion of the ICA
28
Structures separating nerves in the IAC
falciform crest separates superior and inferior nerves; Bill's bar separates CN 7 from superior vestibular nerve
29
Vessel giving rise to middle meningeal artery
maxillary artery (off ECA)
30
Nervus intermedius
a.k.a. nerve of Wrisberg; part of CN 7; runs with facial nerve in anterior-superior IAC; joins with CN 7 at geniculate ganglion
31
Complications of cervical ICA dissection
partial Horner's syndrome (ptosis, miosis), MCA stroke
32
Aneurysm with origin at the dural ring
buzzword (phrase) for supraclinoid ICA aneurysm
33
Petrolingual ligament
forms proximal dural ring; marks beginning of C4 segment of ICA (cavernous)
34
Vessels above and below CN 3
PCA above, SCA below
35
Relationship of P-comm to CN 3 in fetal PCA
P-comm is superior-lateral to CN 3; normally P-comm is superior-medial to CN 3
36
Persistent carotid-vetebrobasilar anastomoses
persistent trigeminal a., persistent otic a., persistent hypoglossal a., persistent proatlantal a. (type 1 = from ICA, type 2 = from ECA)
37
Causes of pulsatile tinnitus
idiopathic intracranial hypertension, aberrant ICA, persistent stapedial a., glomus jugulare or tympanicum, dural AVF (when involving sigmoid sinus)
38
Causes of pulsatile exophthalmos
carotid-cavernous fistula, sphenoid wing dysplasia
39
Vessels that form aberrant ICA
inferior tympanic a. (from ascending pharyngeal a.) and caroticotympanic a. (from petrous ICA); due to failure in formation of cervical ICA
40
Aberrant ICA association
persistent stapedial a. (30% of the time)
41
Absent foramen spinosum
persistent stapedial a.; gives rise to middle meningeal a.; enlargement of anterior tympanic segment of facial n. canal
42
Venous drainage of cavernous sinus
superior petrosal sinus (to transverse sinus) and inferior petrosal sinus (to extracranial IJV)
43
Vein coursing along the roof of the 3rd ventricle
internal cerebral veins (paired); originate at foramen of Monro; drain to great vein of Galen
44
Vein coursing through the ambient cisterns
basal veins of Rosenthal (paired); originate along medial temporal lobes; drain to great vein of Galen; course is similar to PCA and CN 4
45
Drainage of veins of Trolard and Labbe
Trolard drains to superior sagittal sinus; Labbe drains to transverse sinus
46
Superficial middle cerebral vein
a.k.a. Sylvian vein; runs along Sylvian fissure; drains to cavernous sinus, as well as veins of Trolard and Labbe
47
Treatment of venous gas introduced during IV placement
none; should resolve within 48 hours
48
Causes of CN 3 palsy
P-comm aneurysm, uncal herniation; pupil is "down & out", ptosis
49
Enhancement of multiple cranial nerves DDx
Lyme disease, mets (CSF spread), MS, ADEM
50
First sign of hydrocephalus
temporal horns dilate first
51
Causes of pachymeningeal enhancement
intracranial hypotension, post-op/post-LP/post-shunting, granulomatous disease, neoplasm (focal)
52
Causes of leptomeningeal enhancement
meningitis, leptomeningeal carcinomatosis, neurosarcoidosis, viral encephalitis, lymphoma, slow vascular flow
53
Findings in intracranial hypotension
pachymeningeal thickening/enhancement, sagging of brainstem and tonsils, distended veins/sinuses, +/- subdural hygromas/hematomas
54
Idiopathic intracranial hypertension associations
hypothyroidism, Cushing's, vitamin A toxicity; slit-like ventricles, empty sella, tortuous optic nerves with dilated sheaths, flattening of posterior globes
55
Causes of non-obstructive communicating hydrocephalus
choroid plexus papilloma, NPH, ex vacuo dilitation
56
Causes of obstructive communicating hydrocephalus
SAH, meningitis, leptomeningeal carcinomatosis
57
Treatment for NPH
shunting; "ventricular size out of proportion to atrophy"
58
Blood-brain barrier in cytotoxic vs. vasogenic edema
cytotoxic = intact BBB (failure of Na/K pump); vasogenic = disrupted BBB (increased capillary permeability)
59
Complication of subfalacine herniation
ACA compression => ACA infarct
60
Effacement of ipsilateral suprasellar cistern
uncal herniation (a.k.a. downward transtentorial); uncus and hippocampus herniate through tentorial incisura
61
Duret hemorrhages
seen in downward transtentorial herniation; due to compression of basilar artery perforators
62
Large infarct with ipsilateral hemiparesis
uncal herniation => compression of contralateral peduncle/midbrain on tentorium => ipsilateral hemiparesis
63
Signs of ascending transtentorial herniation
flattening of quadrigeminal cistern ("smile"), severe hydrocephalus, "spinning top" sign (bilateral posterior midbrain compression)
64
Size criteria for tonsillar herniation
>5 mm for single tonsil, or both tonsils >3 mm
65
Symmetric parietoccipital white matter edema
PRES; does not restrict; due to acute HTN, chemo, eclampsia, sepsis
66
Radiation-induced demyelination
T2 bright (edema) => atrophy; chemo can do the same thing; may see mineralizing microangiopathy in kids
67
What vitamin is thiamine?
vitamin B1; thiamine deficiency => Wernicke encephalopathy; involves mammillary bodies, medial thalamus, periaqueductal gray
68
Optic nerve atrophy + putaminal hemorrhage
methanol poisoning; may also see subcortical white matter necrosis
69
Stuff alcoholics get...
cerebral atrophy (especially vermal), Wernicke's, Marchiafava-Bignami
70
T2 bright basal ganglia DDx
CO poisoning, Japanese encephalitis, CJD, Leigh syndrome, NF1 (FASI), osmotic demyelination
71
T2 bright basal ganglia + cortex DDx
hypoglycemia, hypoxic-ischemic, CJD
72
T1 bright basal ganglia DDx
hepatic encephalopathy, hyperalimentation, hypothyroidism, Fahr disease
73
Disseminated necrotizing leukoencephalopathy
seen in leukemia patients undergoing chemoradiation; severe white matter changes with ring enhancement
74
Preserved motor strip on FDG-PET
seen in dementia
75
Dementia with hippocampal atrophy
Alzheimer's; temporal horn atrophy >3 mm
76
Most common cause of dementia + 2nd most common cause
Alzheimer's > multi-infarct dementia
77
Binswanger disease
chronic small vessel ischemic disease + dementia; spares subcortical U-fibers; strongly assoc. with HTN
78
Most common TORCH infection
CMV > toxoplasmosis
79
Findings in CMV (TORCH)
periventricular calcifications +/- cysts, polymicrogyria, schizencephaly, cerebellar hypoplasia
80
HSV type in TORCH infection
HSV-2; hemorrhagic infarction => encephalomalacia
81
Most common opportunistic CNS infection in AIDS
toxoplasmosis; cryptococcus is the most common fungal CNS infection in AIDS
82
HIV patient with symmetric T2 WM abnormality sparing U-fibers
HIV encephalitis; CD4 <200; T1 signal is normal; may see assoc. brain atrophy
83
HIV patient with asymmetric T2 WM abnormality involving U-fibers
PML (JC virus); CD4 <50; corresponding low T1 signal
84
White cerebellum sign (CT)
hypoxic-ischemic encephalopathy
85
Ependymal enhancement in HIV patient
consider CMV; may also see atrophy and periventricular hypodensity/high T2 signal
86
T1 dark, T2 bright lesion with ring enhancement in cryptococcus
cryptococcoma; dilated perivascular spaces (filled with gelatinous material) are also T1 dark, T2 bright but should not enhance
87
Characteristics distinguishing toxoplasmosis from lymphoma (3)
toxo does NOT restrict, has decreased CBV, and is PET/thallium cold; lymphoma is the opposite for all of them
88
Basilar meningitis DDx
TB, cryptococcus, neurosarcoid, neurosyphilis, lymphoma, pyogenic infections
89
Basilar meningitis + hydrocephalus
TB
90
Limbic encephalitis association
small cell lung cancer commonly (paraneoplastic syndrome); next step is check for lung cancer
91
West Nile encephalitis findings
high T2 signal in basal ganglia and thalamus; corresponding restricted diffusion
92
Etiology of majority of CJD cases
sporadic; findings include gyriform diffusion restriction, pulvinar sign, and rapidly progressive atrophy
93
Neurocysticercosis stages
vesicular (T1 dark/T2 bright with dot) => colloid (T1/T2 bright + edema) => granular (thicker wall, less edema) => nodular (calcified)
94
Complications of meningitis
venous thrombosis, vasospasm, empyema, ventriculitis, hydrocephalus, cerebritis, abscess; sterile subdural collections (infants)
95
Common causes of ventriculitis
shunt placement, intra-thecal chemo; septa may develop => hydrocephalus; intraventricular extension of abscess is pre-terminal
96
Most common CNS met in peds
neuroblastoma; to orbit, bone, or dura (not usually brain parenchyma)
97
Primary CNS neoplasms that "seed"
medulloblastoma, ependymoma, GBM, oligodendroglioma
98
Most common location for oligodendroglioma
frontal lobe; expands cortex; 1p19q deletion assoc. with better outcome
99
Cortical-based mass with calcification
oligodendroglioma, ganglioglioma
100
CNS neoplasms associated with seizures in kids
PXA, ganglioglioma, DNET
101
PXA in an infant
desmoplastic infantile ganglioglioma (DIG)
102
4th ventricle mass in an adult DDx
choroid plexus papilloma, subependymoma
103
Supratentorial ependymoma
often >4 cm at presentation; may be extraventricular (cerebral hemisphere > 3rd vent. > lateral vent.); large, heterogeneous, cystic and solid; often with calcification and/or hemorrhage
104
Medulloblastoma + dural calcifications
Gorlin syndrome; also keratocysts, basal cell cancers, cardiac fibromas
105
Medulloblastoma associations
Gorlin syndrome, Turcot syndrome (GBMs also)
106
Choroid plexus carcinoma association
Li-Fraumeni syndrome
107
Most common location of intraventricular mets
trigone of lateral ventricle; most common primary is lung or renal
108
Causes of multiple meningiomas
NF2, radiation to head (may also cause capillary telangiectasias)
109
Most common location for a dermoid
suprasellar > posterior fossa
110
T1 hyperintensity in IAC
IAC lipoma; will dropout on fat sat; assoc. with sensorineural hearing loss
111
Most common supratentorial mass
mets
112
Primary CNS lymphoma
solidly enhancing in immunocompetent patients, ring-enhancing (necrosis) in immunocompromised
113
Infant with rapidly increasing head circumference
consider DIG
114
Subgaleal space
between periosteum and scalp aponeurosis
115
Most common location for chordoma
sacrococcygeal > clivus > C-spine; often crosses disc space to involve adjacent vertebral body
116
Dural-based mass DDx
meningioma, mets (breast most commonly), hemangiopericytoma, lymphoma, neurosarcoid
117
First consideration for any suprasellar lesion
could it be an aneurysm?
118
Intrasellar mass (within pituitary) DDx
microadenoma, macroadenoma, Rathke cleft cyst, craniopharyngioma (completely intrasellar is rare), pars intermedia cyst
119
Most common suprasellar mass (adults)
macroadenoma with suprasellar extension; arises from adenohypophysis; >1 cm by definition
120
Suprasellar mass with carotid encasement (no narrowing)
macroadenoma; suprasellar meningiomas may cause carotid narrowing
121
Findings in pituitary apoplexy
fluid level or increased T1 signal representing hemorrhage; causes include Sheehan syndrome and bromocriptine; acute syndrome with headache, visual impairment, and panhypopituitarism; most often occurs in an existing adenoma or peri-/postpartum
122
Rathke cleft cyst with small enhancing nodule
craniopharyngioma; Rathke cleft cysts do not enhance (may see enhancing rim of compressed pituitary tissue)
123
Midline suprasellar mass with restricted diffusion
epidermoid cyst
124
Differences between types of craniopharyngioma
adamantinomatous = cystic areas, calcs, recur more often; papillary = no cystic areas, no calcs, recur less often
125
Most common location of germinoma
pineal > suprasellar; 10-19 y/o most commonly, almost only in boys; restrict diffusion, enhancing
126
Enhancement pattern of hypothalamic hamartoma
do NOT enhance (consider alternative diagnosis if enhancement); gelastic seizure, precocious puberty
127
Pineal mass with exploded calcifications
pineoblastoma (2nd decade, invasive) vs. pineocytoma (4th-5th decade, non-invasive)
128
Increased FLAIR signal in subarachnoid space DDx
subarachnoid hemorrhage, meningitis, leptomeningeal carcinomatosis, recent oxygen or propofol, residual contrast
129
Multiple areas of susceptibility in brain parenchyma DDx
hypertensive microhemorrhages, CAA, familial cavernomas, DAI, hemorrhagic mets
130
Dysplastic cerebellar gangliocytoma
a.k.a. Lhermitte-Duclos; assoc. with Cowden syndrome
131
Recurrent laryngeal nerve course
right recurs around the right subclavian, left recurs at the AP window
132
Appearance of cerebral contusion
may appear as small patchy hyperdense foci of hemorrhage or larger coalescent hemorrhage (hematoma)
133
Most sensitive sequence for SAH
FLAIR; most common cause of SAH is trauma (not aneurysm rupture); vasospasm at 4-14 days typically
134
Fracture locations in LeFort system
1 = lateral nasal aperture; 2 = medial orbital rim + orbital floor; 3 = lateral orbital rim/wall + zygomatic arch; always pterygoid process
135
Timing of stages of blood
hyperacute = 0-6 hours; acute = 6-72 hours; early subacute = 3-7 days; late subacute = 1 week to months; chronic is old
136
Swirl sign (CT)
active bleeding; low attenuation blood is hyperacute and non-clotted
137
Airless expanded sinus
mucocele; often T1 bright with thin rim enhancement
138
Most common type of temporal bone fracture
longitudinal
139
Most common type of temporal bone fracture to involve ossicles
longitudinal; results in conductive hearing loss
140
Sequelae of transverse temporal bone fractures
sensorineural hearing loss, facial nerve and/or vascular injury
141
Symptoms of superficial siderosis
sensorineural hearing loss, ataxia
142
Most common location for hypertensive hemorrhage
basal ganglia > pons and cerebellum
143
Treatment of non-hemorrhagic stroke
IV tPA within 3 hours or IA tPA within 6 hours (from symptom onset); must be no hemorrhagic transformation and the area of hypodensity must be <1/3 of MCA territory
144
Watershed infarcts in a kid
moyamoya
145
Patients at increased risk for hemorrhagic transformation of infarct
on anticoagulation, received tPA, large embolic infarcts, venous infarcts
146
Patients at increased risk for venous thrombosis/infarction
dehydration (babies), mastoiditis (kids), coagulopathies, OCPs
147
Patients at increased risk for intracranial aneurysm formation
smokers, ADPKD, Marfan's, Ehlers-Danlos, aortic coarctation, AVMs
148
Most common location for intracranial aneurysm
anterior circulation > posterior; A-comm in anterior circulation; basilar tip > PICA in posterior circulation
149
Increased risk of aneurysm rupture
increased size, posterior location, prior SAH, smokers, females
150
Fusiform intracranial aneurysm associations
PAN, connective tissue diseases, syphilis; most commonly affect posterior circulation
151
Pedicle aneurysm
found on artery feeding an AVM; majority of AVM-assoc. aneurysms occur within the nidus; high bleeding risk
152
Blister aneurysm
broad-based; located at a non-branch point (supraclinoid ICA most commonly)
153
Size limit for P-comm infundibulum
≤3 mm
154
Increased bleeding risk in AVMs
smaller size, single draining vein, intranidal or perinidal aneurysm, basal ganglia/thalamic/periventricular location
155
Increased bleeding risk in dural AVFs
direct cortical venous drainage; dural AVFs are acquired due to dural venous thrombosis, seen in 50-60 y/o
156
Low flow vascular lesions (intracranial)
cavernoma, DVA, capillary telangiectasia
157
Vascular lesions occult on angiography
cavernoma, capillary telangiectasia
158
Risk factors for vasospasm in SAH
SAH >1 mm in thickness, intraventricular or parenchymal extension of hemorrhage; occurs 4-14 days after SAH
159
Causes of vasospasm
SAH, meningitis, PRES, migraines; smooth, long stenoses; often involves multiple vascular territories; may cause infarction
160
MR sequence for carotid dissection
T1 fat sat (crescent of bright blood)
161
Most common vasculitis to involve CNS
PAN; all vasculitides demonstrate a beaded appearance with multifocal areas or narrowing
162
Most common collagen vascular disease to involve CNS
SLE
163
Moyamoya associations
sickle cell disease, NF1, prior radiation, Down syndrome; may cause watershed infarction (peds) or hemorrhage (adults)
164
Thunderclap headache with multifocal narrowing on CTA (no SAH)
consider reversible cerebral vasoconstriction syndrome (RCVS); may result in infarction
165
CADASIL
frontal and temporal white matter disease (high T2); h/o migraines and/or strokes/TIAs; may progress to dementia
166
NASCET criteria for measuring carotid stenosis
maximum ICA stenosis compared to a parallel (non-curved) segment of the distal cervical ICA; (1-(A/B))*100
167
Colpocephaly associations
anything assoc. with callosal dysgenesis (pericallosal lipoma, Chiari II, Dandy-Walker, holoprosencephaly)
168
Iniencephaly
"star-gazing fetus"; deficit of occipital bones, enlarged foramen magnum
169
Arhinencephaly
no olfactory bulbs or tracts; assoc. with Kallman syndrome
170
Rhombencephalosynapsis
vermal aplasia with fused cerebellar hemispheres ("single-lobed cerebellum")
171
Joubert syndrome associations
retinal dysplasia, MCDK; molar tooth malformation + hepatic fibrosis = COACH syndrome
172
Dandy-Walker (classic) findings
cystic dilation of 4th ventricle, enlarged posterior fossa, torcular-lambdoid inversion, vermal hypoplasia; often with hydrocephalus
173
Dandy-Walker spectrum variants
ventriculocele = large 4th erodes occipital bone; variant = normal-sized PF, variable vermian hypoplasia, no or small cyst; blake pouch cyst = normal-sized PF, open 4th communicates with cyst; MCM = enlarged PF, retrocerebellar CSF space >10 mm
174
Direction of cerebral cleavage
posterior to anterior (think of holoprosencephaly)
175
Absent septum pellucidum associations
septo-optic dysplasia, schizencephaly, holoprosencephaly
176
Holoprosencephaly associated findings
cyclops eye, pyriform aperture stenosis, mega-incisor
177
Enlarged cerebral hemisphere + enlarged ventricle
hemimegalencephaly; "hamartomatous overgrowth"; may have pachygyria, polymicrogyria, heterotopia
178
Number of layers of cortex in lissencephaly
4 layers
179
Type of lissencephaly associated with band heterotopia
type 1 (classic)
180
Most common gray matter heterotopia
subependymal
181
Schizencephaly associations + most common type
optic nerve hypoplasia, absent septum pellucidum, epilepsy; most common type is open lip (80%); lined by gray matter
182
Cortical mantle + falx present
hydrocephalus; if no falx => holoprosencephaly
183
Cephalocele
generic term for herniation of brain contents; may represent an encephalocele or meningocele
184
Chiari I association
syrinx, Klippel-Feil syndrome, hydrocephalus; tonsilar herniation >5 mm, "peg-like" morphology
185
Chiari II associations
myelomeningocele, syrinx, callosal dysgenesis, lacunar skull; hydrocephalus seen in 90%
186
Most common craniosynostosis
scaphocephaly (dolicocephaly)
187
Brachycephaly + Wormian bones + absent clavicles
cleidocranial dysostosis
188
Brachycephaly + syndactyly + facial hypoplasia
Apert syndrome
189
Brachycephaly + maxillary/mandibular hypoplasia + exophthalmos
Crouzon syndrome
190
Sinus pericranii
low flow communication between a dural venous sinus and extracranial veins (via emissary veins); osseous defect present
191
Most common cause of macrocephaly
BESSI; resolves without treatment within 2 years; assoc. with increased risk of subdural bleed
192
Choanal atresia associations
CHARGE, Crouzon's, DiGeorge syndrome, Treacher-Collins, fetal alcohol syndrome; unilateral > bilateral; bony > membranous
193
MELAS (acronym)
mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes; increased lactate, decreased NAA
194
Most common leukodystrophy
metachromatic
195
Leukodystrophies with big heads
Alexander disease, Canavan disease
196
Adrenoleukodystrophy gender predilection
only in boys (sex-linked); 5-10 y/o (other leukodystrophies are generally <5 y/o)
197
Three normal peaks in MR spectroscopy
Choline, Creatine, and N-acetyl aspartate; form Hunter's angle (plane taking off)
198
MR spect: decreased NAA, increased lactate
MELAS
199
MR spect: elevated NAA peak (higher than normal)
Canavan disease
200
MR spect: elevated alanine
meningioma
201
MR spect: elevated glutamine
hepatic encephalopathy
202
MR spect: significance of Cho and lactate
Cho is a non-specific marker for cell turnover (tumor, infarction, or inflammation); lactate is seen with anaerobic metabolism (necrotic tumors, radiation necrosis, abscess)
203
MR spect: decreased Cho, decreased NAA, elevated lactate
radiation necrosis
204
MR spect: elevated Cho, decreased NAA, elevated lactate
high-grade malignancy (e.g. GBM)
205
Most common primary petrous apex lesion
cholesterol granuloma; most common symptom is hearing loss; may require surgery if rapidly growing
206
Petrous apex cholesteatoma - congenital or acquired
congenital
207
Petrous apex lesion with smooth expansile bony change
cholesterol granuloma or cholesteatoma
208
Complication of petrous apicitis extending into Dorello's canal
Gradenigo syndrome; petrous apicitis + facial pain (trigeminal neuropathy) + lateral rectus palsy; involves Meckel's cave and Dorello's canal
209
Petrous apicitis is a complication of...
otomastoiditis; may progress to skull base osteomyelitis, ICA vasospasm, meningitis, venous sinus thrombosis
210
Endolymphatic sac tumor MR characteristics
T2 bright, avid enhancement, +/- flow voids; amorphous calcifications on CT; tumor blush on angiography; assoc. with VHL
211
Most common presenting symptom of paraganglioma
hoarseness (from vagal nerve compression); "salt-and-pepper"; often hereditary and multiple
212
Most common cause of congenital sensorineural hearing loss
enlarged vestibular aqueduct; hearing loss is progressive, often bilateral; assoc. with Mondini triad and absence of bony modiolus
213
Enhancement in cochlea and/or semicircular canals
labyrinthitis; viral cause most often
214
Labrynthitis ossificans findings
increased density (CT) or low T2 signal in labyrinthine structures; healing response to prior infection or trauma
215
Fenestral otosclerosis - conductive or sensorineural hearing loss?
conductive; fenestral otosclerosis occurs at fissula ante fenestram
216
Retrofenestral otosclerosis - conductive or sensorineural hearing loss?
conductive + sensorineural; retrofenestral type is almost always bilateral
217
Patients at increased risk for otitis media
children, Down syndrome; due to horizontal orientation of eustachian tubes; >6 weeks = chronic
218
Complications of otitis media
coalescent mastoiditis, facial nerve palsy, dural sinus thrombosis, meningitis, labyrinthitis
219
Bezold abscess
complication of otomastoiditis; infection erodes through bone to form an abscess deep to the sternocleidomastoid
220
Order of destruction in cholesteatoma
scutum => long process of incus (+/- other ossicles) => LSCC (may result in labrynthine fistula)
221
Most common type of cholesteatoma (middle ear)
pars flaccida > pars tensa; flaccida is flimsy and at the top; tensa is tough and at the bottom; may be congenital or acquired
222
Noise-induced vertigo
a.k.a. Tulio's phenomenon; seen in dehisence of the superior SCC
223
Michel aplasia
complete labyrinthine aplasia; absence of inner ear structures
224
Necrotizing (malignant) external otitis associations
almost always in diabetics; Pseudomonas (98%); soft tissue swelling, bony destruction, +/- abscesses
225
Non-enhancing segments of facial nerve
cisternal, canalicular, and labyrinthine; tympanic and mastoid segments normally enhance (perineural venous plexus)
226
Enhancing facial nerve DDx
Bell's palsy, Lyme disease, Ramsay Hunt syndrome (VZV), perineural spread of malignancy (parotid), schwannoma
227
Ramsay Hunt syndrome
due to VZV infection; CN 7 palsy (facial paralysis), sensorineural hearing loss, vesicular rash of external ear
228
Enhancing lesion in geniculate ganglion area with bony spicules
facial nerve venous malformation (or hemangioma); facial paralysis (CN 7 palsy)
229
Nerve involvement in Lyme disease
CN 7 > CN 3 and CN 5; multiple enhancing cranial nerves, periventricular/spinal cord white matter lesions (high T2)
230
EAC exostoses
due to cold water exposure (surfers classically); always bilateral; most common symptom is conductive hearing loss
231
Enhancing lesion in geniculate ganglion area
facial nerve schwannoma, facial nerve cavernous malformation
232
Location of glomus tympanicum
cochlear promontory; arises from Jacobson's nerve
233
Intracranial complications of Paget disease
hearing loss, CN palsies, secondary osteosarcoma, basilar impression (may compress brainstem or cause hydrocephalus)
234
Basilar impression (acquired) DDx
RA, Paget's, ankylosing spondylitis, osteomalacia/rickets, osteogenesis imperfecta, mucopolysaccharidoses
235
Basilar invagination (developmental) DDx
Chiari I, Chiari II, Klippel-Feil, atlanto-occipital assimilation, achondroplasia, Down syndrome
236
Nasal mass with nose bleeds
JNA; originates in sphenopalatine fossa, spreads to PPF and nasopharynx; bone remodeling +/- destruction
237
Widened maxillary ostium
buzzword for antrochoanal polyp; peripheral enhancement with NO central enhancement, smooth bony remodeling; teenagers
238
Cerebriform enhancement
inverted papilloma; originates at middle meatus, may extend into maxillary sinus; bony remodeling; 40-70 y/o; risk of malignant transformation to SCC (look for bony destruction and/or necrosis)
239
Nasopharyngeal mass that is hot on octreotide
esthesioneuroblastoma; intracranial posterior cyst is classic; 2nd and 6th decades (bimodal)
240
Most common location for SNUC
arises from ethmoids most commonly; highly aggressive malignancy of paranasal sinus
241
Most common etiology of epistaxis
bleeding from anterior septum (Kiesselbach plexus); posterior sources are less common, but more difficult to treat (sphenopalatine a.)
242
Ranulas arise in what space?
sublingual space; "plunging" = beyond mylohyoid muscle (through or around)
243
Sialolithiasis most common in which duct?
Wharton's duct (submandibular); may lead to sialoadenitis (acute) or fatty atrophy of gland (chronic)
244
Determinant of spread of odontogenic infection
attachment of mylohyoid muscle to inner mandible; infection above = sublingual spread; infection below = submandibular spread (includes 2nd/3rd molars)
245
Most common masticator space mass (adult)
odontogenic abscess
246
Causes of mandibular osteonecrosis
prior radiation, bisphosphonates
247
Cyst associated with the crown of an unerupted tooth
dentigerous cyst (a.k.a. follicular cyst); displace and resorb adjacent teeth
248
Odontogenic keratocyst characteristics
expands longitudinally in mandible; expansile, solitary, unilocular (most commonly); assoc. with Gorlin syndrome
249
Ameloblastoma characteristics
expansile, multiloculated, "soap bubbly"; may see enhancing mural nodule or septa; typically assoc. with unerupted tooth
250
Most common salivary gland tumor (major and minor glands)
benign mixed tumor (a.k.a. pleomorphic adenoma); in parotid, 90% are in superficial lobe; treatment is excision
251
Warthin's tumor association
smokers; may be bilateral, only occurs in parotid; hot on pertechnetate and PET
252
Most common primary parotid gland malignancy
mucoepidermoid carcinoma; assoc. with prior radiation
253
Most common primary submandibular and sublingual gland malignancy
adenoid cystic carcinoma; perineural spread (CN palsies and paresthesias)
254
Multiple parotid masses DDx
mets, lymphoma (NHL), Warthin tumors, benign mixed tumors (seeding from post-op spillage), Sjogren's, HIV lymphoepithelial lesions, sarcoidosis
255
Complication of Sjogren's (parotid)
lymphoma (MALT-type NHL); Sjogren's is most commony seen in middle-aged females
256
Painless parotid swelling
benign lymphoepithelial lesions, sarcoidosis; as opposed to parotitis which is presents as painful swelling
257
Uveoparotid fever
bilateral uveitis, parotid enlargement, facial nerve palsy; considered pathognomonic for sarcoidosis
258
Three classic tumors arising in the post-styloid parapharyngeal space
a.k.a. carotid space; paraganglioma, schwannoma, neurofibroma
259
Axial level carotid body tumor vs. glomus vagale
carotid body tumor occurs at the level of the floor of the mouth; glomus vagale occurs at the level of the nasopharynx or palate
260
Suprahyoid neck compartments in which a schwannoma can arise
carotid space (CN 9/10/11/12), parotid space (CN 7), masticator space (CN V3), parapharyngeal space (CN V3 branches)
261
Nodes of Rouviere
retropharyngeal, off-midline, at the level of the nasopharynx; suppurative nodes may appear cystic
262
Thick rim-enhancing cervical nodes with central necrosis
tuberculous cervical lymphadenitis (scrofula); +/- nodal calcification; neck is most common extra-thoracic site for TB nodes
263
Low density lesion DDx (neck)
SCC nodal mets, suppurative lymph nodes, 2nd branchial cleft cyst, lymphatic malformation, TB nodal involvement, thyroid cancer mets, thyroglossal duct cyst
264
Grisel syndrome
torticollis (atlantoaxial rotatory subluxation) related to respiratory infection or ENT surgery
265
Roles of muscles of mastication
lateral pterygoid opens mouth, medial pterygoid, temporalis, and masteter close mouth
266
Boundaries of oropharynx, hypopharynx, and larynx
oropharynx = palate to hyoid; hypopharynx = hyoid to esophagus; larynx = hyoid to trachea
267
Boundaries of lymph node level IIA
anterior = posterior submandibular gland; posterior = posterior margin of IJV; inferior = inferior margin of hyoid bone
268
Boundaries of lymph node level III
posterior = posterior margin of SCM; superior = inferior margin of hyoid bone; inferior = inferior margin of cricoid cartilage
269
Suspected 2nd branch cleft cyst
must consider could this be metastatic SCC
270
Most common location for nasopharyngeal SCC
fossa of Rosenmuller; mucosal elevation just anterior is the torus tubarius; SCC may present as a unilateral mastoid effusion
271
Most common location for laryngeal SCC
glottic (also the type with the best prognosis)
272
Fixation of vocal cords (T-stage in SCC)
at least T3
273
Tumor on both sides of cricoid cartilage (laryngeal SCC)
compatible with cricoid invasion => contraindication to laryngeal conservation surgery
274
Causes of laryngocele
SCC (ipsilateral), glass-blowing, wind instrument players, chronic coughers; may be air or fluid-filled
275
Findings in vocal cord paralysis
paramedian true cord, ballooning of ipsilateral ventricle, enlarged ipsilateral pyriform sinus
276
Findings in chronic allergic fungal sinusitis
central hyperdensity/low T2 signal with peripherally enhancing mucosa; expanded sinus
277
Patient at risk for acute invasive fungal sinusitis
diabetics, immunocompromised patients; look for bony destruction and extension of enhancement outside of sinus
278
Coloboma associations
CHARGE (especially if bilateral), trisomy 13, trisomy 18, VATER
279
Microphthalmia + increased density of vitreous DDx
Coat disease vs. PHPV; both may lead to retinal detachment; Coat disease is seen in boys
280
Bilateral microphthalmia + intraocular calcifications
retinopathy of prematurity; may also have increased density of vitreous; seen in premature infants on prolonged oxygen; bilateral
281
MR characteristics of orbital pseudotumor
low T2 signal, enhancing; painful proptosis; involves lateral rectus most commonly
282
Tolosa-Hunt syndrome
essentially orbital pseudotumor involving the cavernous sinus; presents with multiple cranial nerve palsies
283
Most common benign and malignant orbital masses (peds)
dermoid and rhabdomyosarcoma, respectively
284
Ill-defined orbital mass DDx
orbital cellulitis, pseudotumor, infantile hemangioma, lymphatic malformation, plexiform neurofibroma, lymphoma, sarcoid, Wegener's, rhabdomyosarcoma
285
Orbital lymphoma association
Chlamydia Psittaci (MALT-type); painless proptosis (downward)
286
Orbital mass with fluid-fluid levels
lymphatic malformation; peds usually; extraconal most commonly
287
Most common cause of spontaneous orbital hemorrhage
orbital varix; distend with provocative maneuvers; may thrombose => pain
288
Round rim-enhancing lesion in lacrimal fossa
dacryocystitis
289
Treatment for subperiosteal abscess (orbit)
surgical emergency for any concerning symptoms (e.g. visual impairment, pain/pressure)
290
Most common orbital mass (adult)
orbital cavernous venous malformation (a.k.a. hemangioma); intraconal most commonly; T2 bright, enhancing
291
Balo and Marburg MS variants
Balo (concentric) = younger patients, alternating concentric bands; Marburg = fulminant form of MS, death within months
292
Origin of artery of Ademkiewicz
originates from the aorta (on the left) at T8-T11; "hairpin" turn on DSA
293
Exiting nerve root at C4-5
exiting = C5 root
294
Exiting nerve root at L4-5
exiting = L4 root (descending root is L5)
295
Cause of epidural lipomatosis
corticosteroids
296
Medications to hold prior to LP (and duration)
moderate bleeding risk (see SIR tables)
297
Complications of spine surgery
residual disk, epidural fibrosis, arachnoiditis, conjoined nerve roots; nerve root enhancement >6 weeks post-op is abnormal
298
Most common type of odontoid fracture
type 2; both type 2 and 3 are unstable
299
Os odontoideum association
Morquio's syndrome; prone to subluxation and instability; orthotopic = on top of dens; dystopic = fused to clivus
300
Anterior cord syndrome
impaired motor function and pain/temperature sensation; proprioception and vibration are intact (dorsal columns)
301
Normal atlanto-dental (atlanto-axial) and basion-dental intervals
atlanto-dental <2.5 mm (or <5 mm in peds); basion-dental interval <12 mm
302
Atlanto-axial instability associations
JIA, Down syndrome, Klippel-Feil, achondroplasia, os odontoideum, fracture; may result in rotatory subluxation with head stuck in a torticollis-like position
303
Spinal cord syndrome: upper extremity deficit worse than lower
central cord syndrome
304
Most common level for pars interaticularis defects
L5-S1 (90%); results in spondylolisthesis
305
Open spinal dysraphism
a.k.a. spina bifida aperta or cystica; myelomeningocele (98%) or myelocele; NO skin covering
306
Open spinal dysraphism (myelomeningocele) associations
Chiari II, diastematomyelia, kyphoscoliosis, syrinx
307
Closed spinal dysraphism
dorsal dermal sinus, lipomyelomeningocele, diastematomyelia, terminal myelocystocele, thickened filum, intradural lipoma, meningocele; skin covering present
308
Tethered cord associations
caudal regression syndrome, VACTERL, most open or closed spinal dysraphisms
309
Thickened filum terminale
>2 mm at L5-S1, low-lying conus; may be assoc. with fibrolipoma (fatty filum) or terminal lipoma; clinical syndrome is tethered cord
310
Lipomyelomeningocele
cord tethered to a dorsal lipoma (often blends with dorsal subcutaneous fat)
311
Terminal myelocystocele
hydromelic tethered cord traversing dorsal meningocele to terminate in dilated terminal ventricle cyst
312
Dermal sinus association
epidermoid or dermoid; dermal sinus extends inward from skin surface; epithelium-lined
313
Most common type of spinal arteriovenous lesion
type 1 (dural AVF)
314
Type 2 arteriovenous lesion (AVM)
intramedullary nidus of AVM from anterior or posterior spinal artery; assoc. with HHT and Klippel-Trenaunay-Weber
315
Foix Alajouanine syndrome
myelopathy assoc. with dural AVF (due to venous hypertension); lower extremity weakness and sensory deficits
316
Most common pathogen in osteomyelitis
S. aureus; phlegmon enhances, abscess contents does not
317
Brucellosis osteomyelitis (spine)
favors L-spine and SI joints, can spare disc similar to TB; from cow's milk or farm exposure
318
Long segment cord myelopathy
transverse myelitis, NMO, cord infarct; MS and ADEM usually involve a shorter area; must consider tumor
319
Causes of transverse myelitis
post-infectious, post-vaccination, SLE, Sjogren's, paraneoplastic, AVMs; 'acute partial' type (<2 segments) is more likely to develop MS
320
Increased T2 signal in dorsal columns
subacute combined degeneration (B12 deficiency), HIV vacuolar myelopathy
321
"Owl eye" appearance of cord
anterior cord infarct; cord infarcts are typically >2 segments
322
Lateral meningocele associations
NF1, connective tissue diseases (e.g. Marfan's)
323
Empty thecal sac sign
ararchnoiditis; may also see nerve root clumping
324
Enhancing nerve roots (spine) DDx
Guillain-Barre syndrome, CIDP, Charcot-Marie-Tooth (inherited); CIDP and CMT demonstrate nerve root thickening and develop over a longer period of time (>8 weeks)
325
Most commonly affected cranial nerve in GBS
CN 7; assoc. with Campylobacter; may also be post-viral or post-vaccination; ascending flaccid paralysis
326
Intradural-extramedullary lesions
schwannoma, neurofibroma, meningioma, dermoid cyst, epidermoid cyst, drop mets (e.g. medulloblastoma)
327
Intramedullary lesion with T2 dark cap
ependymoma; T2 dark cap represents hemorrhage; assoc. with NF2 (especially if in a child)
328
Most common cause of intramedullary mets (spine)
lung cancer
329
Treatment of spinal schwannomas vs. neurofibromas
schwannoma may be resected with a nerve-sparing approach; neurofibroma requires nerve resection
330
Lytic sacral lesion DDx (adult)
mets, chordoma, lymphoma, GCT, ABC, myeloma, chondrosarcoma, Paget's, insufficiency fracture
331
Child with seizures, hemiparesis, and port-wine stain nevus
Sturge-Weber; pial angiomatosis, cortical calcifications, cortical atrophy, ipsilateral enlarged choroid plexus
332
Duct draining sublingual glands
duct of Rivinus
333
Duct draining parotid glands
Stensen's duct
334
Accessory parotid gland location
anterior to parotid gland, superficial to masseter m.; commonly bilateral
335
Sinonasal polyposis
extensive remodeling and erosion of the nasal cavity and paranasal sinuses; assoc. with Samter's triad (nasal polyposis, aspirin intolerance, asthma)
336
Nerve involvement in vocal cord paralysis
recurrent laryngeal n. > superior laryngeal n.
337
Features of vocal cord paralysis
thyroarytenoid m. and posterior cricoarytenoid m. atrophy, ipsilateral paramedian vocal cord, ipsilateral enlarged laryngeal ventricle/pyriform sinus; left > right, bilateral > unilateral
338
Laryngocele
ipsilateral and fluid-filled if related to neoplastic obstruction
339
Most common nerve schwannoma arises from
superior vestibular nerve (CN 8)
340
Size of a giant cerebral aneurysm
>2.5 cm
341
TOF technique - head vs. neck
3D GRE TOF in the head, 2D GRE TOF in the neck
342
Innervation of the digastric muscle
anterior belly innervated by CN5, posterior belly innervated by CN7 ("Heinz 57")
343
Pendred syndrome
enlarged vestibular aqueduct, absence of bony modeolus, +/- Mondini malformation; assoc. with thyroid goiter
344
Tributaries of the internal cerebral veins
choroidal vein and thalamostriate vein combine to form each internal cerebral vein
345
Most medial cranial nerve
CN6 (not including CN3)
346
Pathologic basal ganglia calcification
Fahr disease, hyperparathyroidism, hypoparathyroidism (also pseudo- and pseudopseudo-), Fabry disease
347
DDx for Tornwaldt cyst
mucous retention cyst, adenoidal hyperplasia
348
Causes of trigeminal neuralgia
compression of CN5 by a vessel, schwannoma, meningioma, or epidermoid
349
Enhancement of microadenoma vs. macroadenoma (pituitary)
microadenomas enhance more slowly than pituitary gland; macroadenomas are heterogeneously hyperenhancing
350
Broca's area
inferior frontal gyrus, a.k.a. pars opercularis
351
Locations without choroid plexus
frontal horns, occipital horns, cerebral aqueduct
