Neuro Brain Flashcards
1
Q
What runs through the cavernous sinus?
A
CN 3, 4, VI, V2, 6, carotid
2
Q
How to find central sulcus (~10 ways)
A
1) pars bracket sign
2) superior frontal sulcus/pre-central sulcus sign-pst end superior frontal sulcus joins pre central sulcus
3) inverted omega (sigmoid hook)-mohot hand
4) bifid posterior central sulcus=posterior CS bifid appearance 85%
5) thin post central gyrus sign-precentral gyrus thicker than post-central gyrus (1.5:1)
6) intraparietal sulcus intersects post-central sulcus
7) midline sulcus sign-most prominent sulcus
3
Q
Pars marginalis & “pars bracket sign”
A
aka marginal sulcus, ramps marginalis.
- Posterosuperior extension of cingulate sulcus separating parental lobule from precuneus of parietal lobe on medial surface of cerebral hemispheres.
- landmark for central sulcus (“pars bracket sign”)-sulcus immediately anterior
4
Q
central sulcus
A
Frontal vs parietal lobes. Immediately pst to motor strip
5
Q
homunculus-ACA and MCA territories
A
ACA=legs
MCA=the rest
6
Q
How many layers in the hippocampus and how does that affect img?
A
- Brighter on FLAIR.
7
Q
Virchow-robins spaces. What/where are they. Significance of enlargement?
A
- Dilated/fluid filled, pial lined perivascular spaces that accompany perforating vessels. Contain interstitial fluid (not CSF). Normal variant, very common.
- locations: lenticulostriate a’s (lower 1/3 bg), centrum semiovale, midbrain
- enlargement-mucopolysaccharidoes (Hurles, Hunters), “gelatinous pseudocysts” in cryptococcal meningitis, advanced age atrophy
8
Q
Cavum variants
A
1) Septum pellucidum- ant to foramen of monroe, btw FH. 100% preterm (15% adults); rarely causes hydro
2) Cavum vergae- SP + pst extension (pst to FOM, btw LV bodies)
3) Cavum velum interpositum- Extension of quadreminal plate cistern to foramen of monroe. Seen above 3rd Vt and below fornices.
- splay fornices
- Unrelated to SP but can coexist.
9
Q
Arachnoid granulation vs venous sinus clot
A
venous sinus clot= linear (AG=round/oval)
10
Q
Arachnoid granulations
A
- projection of arachnoid membrane (villi) into dural sinuses that allow CSF to pass from SAS –> venous system
- in transverse & superior sagittal sinuses
- T2 bright
11
Q
tentorial notch
A
separates sup from inf tentorium
12
Q
major anatomic components of midbrain
A
- Ant –> post:
- Cerebral peduncles-WM tracts
- tegmentum- CN nuc (8 from sup coll level, 9 from inf coll level), GM nuc (substantia nigra, red nucleus, periaquaductal grey), WM tracts
- tectum (quadreminal plate-sup (visual pw) & inf colliculi (auditory pw)
- cerebral aquaduct passes btw teg & tectum
- surrounding cisterns: interpeduncular, quadrigeminal, ambient
13
Q
substantia nigra
A
pigmented nucleus, through mb from pons –> sub thalamic region. Imp for mvmt
- pars compacta-dopaminergic cells (PD)
- pars reticularis-GABAergic cells
14
Q
red nucleus
A
- relay and control station for cerebellar, GP, and CM impulses
- imp for m tone, posture, locomotion
15
Q
periaquaductal GM
A
- Surrounds cerebral aqueduct
- Imp in modulation pain, defensive behavior
16
Q
Pars nervosa-contents?
A
“nervous guy in front”
-CN9, Jacobson’s nerve (tympanic branch)
17
Q
Jacobson’s nerve
A
tympanic branch of cn 9
18
Q
Pars vascularis
A
jugular bulb, CN 10, Arnold’s n (auricular branch), CN 11
19
Q
7Up, COKE Down
A
orientation of CN 7 to cochlear branch CN 8 in internal auditory canal (IAC)
-superior vestibular branch sup to inferior
20
Q
ideal sequence to see CN 7 & 8
A
T2W
21
Q
What’s in it?-Foramen ovale
A
CN V3, accessory meningeal artery
22
Q
What’s in it?-Foramen rotundum
A
CN V2 (R2V2)
23
Q
What’s in it?-Superior orbital fissure
A
CN3, 4, VI, 6
24
Q
What’s in it?-Inferior orbital fissure
A
CN VII
25
What's in it?-foramen spinosum
middle meningeal artery
26
What's in it?-jugular foramen
Pars Nervosa-CN 9
| Pars vascularis-jugular bulb, CN 10, 11
27
What's in it?- hypoglossal canal
CN 12
28
What's in it?- optic canal
CN 2, opthalmic a
29
What's in it?- cavernous sinus
CN 3, 4, VI, VII, 6, carotid artery
30
What's in it?- IAC
CN 7, 8 (cochlear, super & inf vestibular components.). 7up, coke down
31
What's in it?- Meckel cave
trigeminal ganglion
32
What's in it?- Dorello's canal
CN 6, inferior petrosal sinus
33
Branches of external carotid-Some Attending Physicians Love Fucking Over Poor Medical Students
- superior thyroid
- ascending pharyngeal
- lingual
- facial
- occipital
- pst auricular
- maxillary
- superficial temporal
34
temporal tap
poking the head-changes waveform for ECA, not for ICA
35
ICA segments
- C1-cervical. No branches
- C2-petrous
- C3-lacerum
- C4- cavernous
- C5- clinoid
- C6- ophthalmic/supraclinoid
- C7- communicating
36
At which spinal level does ICA & ECA bifurcate?
C3/4
37
Meckel/trigeminal cave/cavity
- CSF containing dural-lined pouch in MCF opening from PCF. Invagination into pstlat cavernous sinus on either side sphenoid bone
- houses trigeminal ganglion
- communicates with prepontine and cerebellopontine cisterns
- ICA is medial
38
ICA segment C1
Cervical.
- No branches
- Atherosclerosis common.
- dissection (spon't in W, Marfans/ED)--> partial Horner's, MCA stroke
- retropharyngeal course--> ENT accidental drainage
39
ICA segment C2
Petrous
- carotid canal
- aneurysms can be surprisingly big (that's what she said)
40
ICA segment C3
Lacerum
- crosses petrolingual ligament
- Meckel's cave exposed via transfacial approach
41
ICA segment C4
Cavernous
- cavernous carotid fistulas
- HTN induced aneurysms
42
ICA segment C5
Clinoid
| -aneurysm compress optic n --> blindness
43
ICA segment C6
Ophthalmic/supraclinoid
- common site aneruysms
- "dural ring"
44
buzzword: origin at the "dural ring"
ICA segment C6/opthalmic/supraclinoid
45
ICA segment C7
Communicating
| -aneurysm --> CN III--> palsy
46
major branches at terminal portion of ICA
opthalmic, anterior choroidal, pst communicating
47
CN3 palsy
1) Pcomm
2) apex basilar artery
3) BA junction w/ superior cerebellar/pst cerebral arteries
48
MC intracranial vascular variant
fetal org PCA
49
Fetal origin PCA
- PCA supplied by anterior circulation (ie: occipital lobe supplied by ICA) --> large Pcomm (larger than P1)
* pcomm superolateral to CN3 (instead of superomedial)
50
Persistent trigeminal artery
- persistent fetal connection btw cavernous ICA to basilar
- increased risk aneurysm
- "tau sign"
51
anastomotic vein of trolard
- superficial middle cerebral vein superior sagittal sinus
- large
- Trolard=Top
52
anastomotic vein of labbe
- superficial middle cerebral v transverse sinus
- small
- Labbe=Lower
53
superficial middle cerebral vein
drains to cavernous sinus
54
superficial and deep intracranial veins
- superficial: superior cerebral v's, superficial middle cerebral v, superior anastomotic v of trolard & labbe
- deep: basal v of Rosenthal, v of Galen, inf petrosal sinus
55
Rolandic vein
in central sulcus
56
what is the relationship btw v of trolard and labbe?
Inverse
57
basal v's of rosenthal
deep v's that pass lateral to midbrain through ambient cistern and drain into v of Galen. Similar course to PCA
58
Vein of galen
big vein "great" formed via union 2 ICVs
59
clinical significance of intracranial collateral venous pathways
Dural sinus accessory drainage into extra cranial vein's.
- regulate T & P
- passage sinus infection/inflammation --> venous sinus thrombosis
60
MC locations venous gas embolus from peripheral/central IV?
- cavernous sinus=MC
| - orbital v, superficial temporal v, frontal venous sinus, petrosal sinus
61
Concha Bullosa
middle concha pneumatized.
- normal variant
- obstructive if large
62
Monro-Kellie Hypothesis
head is closed shell composed of 3 major components which remain in equilibrium: brain, blood, csf.
63
intracranial hypotension
- CSF down --> volume blood increases
- meningeal engorgement (enhancement), distention dural venous sinuses, prominent intracranial vessels, "pituitary pseudo-mass" (enlargement)
64
idiopathic intracranial hypertension (pseudotumor cerebri)
- Etiology not well understood-making too much CSF or not absorbing it
- ass-hypoTh, Cushings, vit A toxicity
- CSF up --> ventricles slit like, pituitary shrinks (partially empty sella), venous sinuses appear compressed, vertical tortuosity of optic nerves & flattening of pst sclera
- downward displacement bs --> stretching CN 6
- bilateral lateral transverse sinus stenosis MOST SPECIFIC
-rx: csf letting, acetazolaminde, lumboperitoneal shunts.
65
Categories of hydrocephalus
- "Communicating"- obstructing or non-obstructing. CSF can exit all ventricles. 25% 4th Vt=N
- "non-communicating-obstructing
66
Where is level of obstruction in obstructive communicating HCP?
- Btw cisterns & arachnoid granulations.
| - MCCs-SAH, meningitis (Tb or bacterial), carcinomatous meningitis
67
Causes of non-obstructive communicating HCP
- brain atrophy (Ex-vacuo)
- NPH
- choroid plexus papilloma
68
culprits of obstruction at...FOM, aqueduct, 4th Vt
- FOM-colloid cyst
- aqueduct-aqueduct stenosis, tectal glioma
- 4th Vt-pst fossa tumor, cerebellar edema/bleed
69
What syx is first and most prominent in NPH?
ataxia
70
is transependymal flow seen more in acute or chronic HCP?
acute
71
findings/buzzwords NPH
- "out of proportion to atrophy." "Wet, wacky, wobbly."
- frontal, temporal horns.
- upward bowing CC
- transependymal flow and/or flow void in aqueduct & 3rd Vt (treated with surgical shunting.)
72
syndrome of hydrocephalus in the young and middle-aged Adult (SHYMA)
NPH but <40 yr old. Less wet, more headache.
73
big 4 causes congenital HCP
1) aquaductal stenosis-MC
2) nt defect, usually chiari II
3) arachnoid cysts
4) DW
74
mcc congenital obstructive HCP
Aqueductal stenosis
75
Aqueductal stenosis
- Web/diaphgram at aqueduct --> dilated LV, 3rd Vt, normal 4th Vt.
- Macrocephaly, thinning of cortical mantle
- rx- shunting, 3rd ventriculostomy
- "sunset eyes"-upward gaze paralysis
76
Bickers Adams Edwards syndrome
- AR aqueductal stenosis variant
| - male w/ flexed thumbs
77
Where is a ventricular shunt normally placed?
- proximally-frontal horn just anterior to foramen of mono
| - distally-peritoneum, pleura or RA
78
imaging to evaluate vt shunt
- non con ct, xray
- rapid single-shot T2 sequence
- US/ct distally for fluid collection
- 0.4 mL pertechnetate
79
causes of vt shunt failure
1) undershunting
2) over shunting
3) infection
4) hydrothorax
5) ascites
80
Causes of undershunting proximal obstructions
- ingrowth of choroid plexus and particulate debris/blood products (mcc)
- catheter migration
- proximal > distal
81
causes of undershunting distal obstructions
- psuedocyst
| - catheter migration (MC in children)
82
"slit like vt's" in setting of vt shunt
-overshunting --> SD hygroma or hematoma (Monroe kelly)
83
vt shunt failure via infection-timing, cultures & img
- w/i 6 mo's
- cultures-blood (-), CSF (+)
- DWI = best (debris in Vts/ventriculitis)
* mild enhancement after placement can be normal
- later: loculations--> restricted flow/obstruction --> isolate/trap 4th vt
84
when do hydrothoraces & ascites matter for vt shunts?
- if symptomatic.
| - ascites may cause inguinal hernias, hydroceles via increased abd P
85
what is vasogenic edema?
Edema tracking through WM via loss of BBB. Tumor, infection, late stage cerebral ischemia, response to steroids
86
sequelae of subfalcine/cingulate herniation
ACA compression --> infarct
87
sequelae of descending transtentorial (uncal) herniation
- uncus & hippo through tentorial incisor.
- effacement IL suprasellar cistern 1st
- duret hemorrhages
- CN3 palsy
- kernohan's notch/phenomenon
88
Mechanism of duret hemorrhages in downward transtentorial herniation
- compression perforating basilar artery branches
| - midline pontomesencephalic junction, cerebellar peduncles
89
Mechanism of CN3 palsy in downward transtentorial herniation
-compression btw PCA & superior cerebellar artery.
90
Kernohan's Notch/phenomenon
- MB on tentorium forms indentation/notch --> IL hemiparesis
| - "false localizing sign"
91
ascending transtentorial herniation
- posterior fossa mass --> upward herniation of vermis
- obstructive hydrocephalus (level of aqueduct)
- "spinning top"-appearance of midbrain from BL compression along pst aspect
- flattening/reversal of quadrigeminal cistern
92
buzzword: spinning top
Appearance of midbrain in ascending transtentorial herniation from BL compression along pst aspect
93
cerebellar tonsil herniation
- occurs after downward transtentorial herniation
| - in isolation = chiari I
94
transcalvarial herniation
herniation brain through fracture
95
osmotic demyelination/central pontine myelinolysis-imaging, earliest change
- T2(+) CENTRAL pons (spares periphery)
- restricted diffusion lower pons-earliest change
- can be extra-pontine (bg, external capsule, amygdala, cerebellum)
96
pseudobulbar palsy
- Ass w/ osmotic demyelination/central pontine myelinolysis.
| - slurred speech, sensitive gag reflex, labile emotional response.
97
Wernicke encephalopathy-cause, triad, img, rx
- B1 (thiamine) (-)
- triad-1) acute confusion 2)ataxia 3) ophthalmoplegia
- img: T2/FLAIR medial/dorsal thalamus (around 3rd Vt), periaqueductal grey, maxillary bodies, tectal plate
- enhancement mam bodies=classic
- MR spect=lactate
- Rx=thiamine replacement.
98
Korsakoff psychosis
- memory loss + confabulation + wernickes (acute confusion, ataxia, ophthalmoplegia)
- -> death
- vit b1 (thiamine) (-)
99
Marchiafava-Bignami-cause, syx's, img, acute vs chronic findings
- middle aged male malnourished alcoholics
- syx's-seizure, m rigidity
- necrosis/demyelination cc (body --> gene --> splenium)
- img: swelling/T2 (+) cc
- "sandwich sign"-preference central fbrs, sparing dorsal/ventral fbrs
- chronic- thinned cc + cystic cavities favoring genu & splenium
- acute=swelling --> chronic = atrophy
100
"sandwich sign"
preferential involvement of central cc fbrs on sagittal img in Marchiafava-Bignami
101
Direct alcoholic injury
-cerebellar (esp vermis) atrophy
102
copper and manganese deposition
T1 bright signal in basal ganglia
| -seen in: liver dx (w/ or w/o hepatic encephalopathy), TPN, Wilson's, non-ketotic hyperglycemia (HNK) (often UL)
103
methanol toxicity
- putaminal T2 bright, ct hyperdensity
| - optic n atrophy, hemorrhagic putaminal & subcortical WM necrosis
104
carbon monoxide
CT hypodense/T2 (+) GP
105
PRES
posterior reversible encephalopathy syndrome 2/2 auto regulation in setting of acute HTN or CRX
- BL asymm pst vasogenic edema cortical & subcortical WM (parietal, occipital regions).
- DOES NOT RESTRICT
- sup frontal sulcus also common!
106
post chemotherapy
* methotrexate
1) PRES- "non classic": bg, bs, cereb; spare occipital lobes
2) leukoencephalopathy-periVt WM BL symm, confluent T2/FLAIR(+)
3) atrophy
4) mineralizing microangiopathy-Ca
5) disseminated necrotizing leukoencephalopathy-severe WM change demonstrating ring enhancement. Classically: leukemia undergoing crx & radiation. Fatal.
107
post radiation-general changes, time frame, long term sequela
1) high T2/FLAIR/atrophy along radiation portal
2) hemosiderin depot & mineralizing microangiopathy in BG, subcortical WM
- acute (days-wks)-too rare, don't care
- early delayed (1-6 mo's)-periVt WM. Reversible
- late delayed (6 mo)- "mosaic", deep WM. Masslike, expansile. Sparing U-fbrs & cc. Progressive, mostly reversible
long term-vasculopathy (strokes, moya-moya), mineralizing microangiopathy, vascular malformations, cancer (meningioma MC s/p 15 yrs;glioma/sarcoma <10 yrs)
108
most important risk factor 1˚ CNS neoplasm
radiation
109
long term sequela s/p radiation
vasculopathy (strokes, moya-moya)
- mineralizing microangiopathy-~2 yrs
- vascular malformations-capillary telangiectasias/cavernous malformations
- cancer (meningioma MC s/p 15 yrs; glioma/sarcoma <10 yrs)
110
heroin inhalation leukoencephalopathy
- symmetric butterfly in centrum semiovale
- pst limb internal capsule (+)
- deep cerebellar WM (+)
- sparing dentate nucleus
111
diagnostic criteria for MS
McDonald
1) disseminated in space (periVt, juxtacortical, infratentorial, sc)-> 1 in at least 2 locs
2) dissemination in time: T2(+), enh + T2(+), no enhancement
112
mc subtype MS
relapsing remitting (85%)
113
MS trivia- most classic finding, most specific finding, brain atrophy, solitary sc involvement, mc location spine, flair vs T2, MR spec, pediatric specifics, acute plaque features
- most classic finding: T2/FLAIR oval & periVt perpendicular lesions
- calloso-septal interface= 98% (helps differentiate it from vascular lesions & ADEM)
- brain atrophy accelerated
- solitary sc involvement can occur usually with brain lesions
- cervical, peripheral lesions
- FLAIR > T2: juxtacortical and periVt plaques
- T2> FLAIR: infratentorial lesions
- MR spec: NAA (-) in plaques
- acute plaques enhance (partially) + restricted diffusion
114
ADEM (acute disseminated encephalomyelitis)
- multiple large T2 bright lesions that enhance in nodular or ring pattern
- DO NOT INVOLVE CALLOSO-SEPTAL INTERFACE
115
Acute hemorrhagic leukoencephalitis (Hurst Disease)
Fulminant form of ADEM with massive swelling & death. Hemorrhage only seen on autopsy (not img).
116
Devics/neuromyelitis optica
transverse myelitis + optic neuritis.
117
Marburg variant
- aka acute, fulminant or malignant MS
- childhood MS variant
- death w/i 1 yr from involvement bs or ME w/ herniation
- febrile prodrome
- MR: extensive confluent areas of tumefactive demyelination w/ mass effect
118
subcortical arteriosclerotic encephalopathy (SAE)
aka Binswanger Disease
- HTN, older people
- multi-infarct dx of WM centrum semiovale. Spares U fbrs
119
CADASIL
Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts & Leukoencephalopathy
- MC hereditary stroke disorder. NOTCH3 mutation chromosome 19
- < 40 yrs + migraine + strokes
- multi-infarct WM in FL, TL (classic). OLs spared
120
motor strip preserved on FDG/PET in which dementia?
degenerative
121
RFs alzheimer
age, DS
122
classic features alzheimers
- hippocampal atrophy (1st, most prom)
| - lower pst temporoparietal atrophy >3mm (>65%)
123
buzzwords: "headphones" or "ear muffs"
Alzheimer FDG pattern: low posterior temporoparietal uptake
124
Amyloid binding tracer
11C PiB (Pittsburgh compound B). Dx Alzheimer
125
multi-infarct dementia aka
vascular dementia
126
RFs Multi-infarct dementia
hyperchol, htn, smoking, CADASIL
127
classic features multi-infarct dementia
cortical & lacunar infarcts. Advanced atrophy. No lobe specificity.
*could knock out motor strip
128
Picks Dementia AKA, classic features
Frontotemporal dementia.
- AD; 40-50s
- compulsive/inappropriate behaviors=being a PRICK
- severe symmetric atrophy of FL > TL
129
dementia with lewy bodies-cause, triad
- alpha synuclein, synucleinopathy
- triad: 1) visual halls 2) spon't PD 3) flucuating ab to concentrate/stay alert
- vs PD: dementia --> motor
130
dementia with lewy bodies-classic img features
- mild generalized atrophy
- vs AD: hippocampi in tact & spares mid pst cingulate gyrus ("cingulate island sign")
- FDG(-) in lateral OL
131
dementia with lewy bodies-classic img features
- mild generalized atrophy.
- FDG(-) in low lateral OL
- vs AD: hippocampi in tact & spares mid pst cingulate gyrus ("cingulate island sign")
132
Fahr Diese (syndrome)/BL Striatopallidodentate Calcinosis/1˚ Familial Brain Ca
BG, thal Ca
| -Globus typically involved first
133
Hallervorden Spaz/PKAN (pantothenate kinase associated neuropathy)
Fe in GP
- T2 dark w/ central high signal via necrosis ("eye of the tiger"
- no enh, no restricted diffusion
134
Amyotrophic Lateral Sclerosis
- Upper motor neuron loss in brain & spine.
- T2/FLAIR rarely (+) in pst int capsule
- Motor band sign on GRE/SWI
135
cortico-basal degeneration
tauopathy
- "alien limb phenomenon" (50%)
- asymmetric FP atrophy
136
MELAS syndrome
mitochondrial disorder: LA, Seizures, Stroked
- (+) lactate doublet at 1.3 ppm
- non vascular GM strokes usually in OL, PL
137
MELAS syndrome
- mitochondrial disorder: LA, Seizures, Strokes
- non-vasc PO GM
- (+) lactate doublet at 1.3 ppm, (-) NAA
- "migrating infarcts"
138
Leigh Disease
- mitochondrial d.o.
- T2/FLAIR (+) in bs, bg, cerebral peduncles
- can restrict, don't enh
- (+) lactate doublet at 1.3 ppm
139
Leigh Disease/Subacute Necrotizing Encephalo-Myelopathy
- mitochondrial d.o.
- GM: bs, bg, cerebral peduncles, periaquaductal. WM: subcortical.
- can restrict, don't enh
- (+) lactate doublet at 1.3 ppm
140
Parkinson Disease
-decreased dopaminergic input to (?+ Fe depo in) pars compact of substantial nigra
-DAT Scan-Ioflupane 123: period-shaped putamen
-mild midbrain volume loss w/ butterfly pattern
?-HY: sparing of midbrain and superior cerebellar peduncles
141
Period-shaped putamen on DAT Scan-Ioflupane 123
Parkinsonism syndrome-PD, MSA, PSP
142
multiple system atrophy (MSA)
- PD Plus...
- highest yield- cerebellar subtype MSA-C: peduncle atrophy w/ shrunken flat pons + enlarged 4th Vt + "hot cross bun sign" (loss of transverse fbrs).
- I-123 MIBG PD vs MSA (cardiac:mediastinal ratio N in MSA)
143
progressive supra nuclear palsy (PSP)/Steele-Richardson-Olszewski
- PD Plus (MC)...
- tauopathy
- micky mouse sign-tegmentum atrophy, sparing tectum + peduncles
- hummingbird sign- mb volume loss w/ concave upper surface relative to pons
144
Wilson disease-What? MC CT & MR findings? Other img findings?
AR hepatic Cu metabolism malfunction --> depo in brain
- "keyser-fleischer rings" (95%)
- MC CT finding-cortical atrophy
- MC MR finding-T1 Bright BG
- T1 & T2 (+) BG, T2(+) dorsal medial thalamus
- panda sign-T2 (+) tegmentum, N dark red nuc & SN
145
Deep brain stimulators-what are they used to treat? Electrode placement?
- Rx for PD, essential terror, chronic pain
| - electrodes in sub thalamic nucleus w/ tips 9 mm from midline (just inside upper most margin of cerebral peduncle)
146
hunter's angle
-line connecting tips of spec peaks, should be 45˚, choline --> Cr --> NAA (alphabetically in increasing order)
147
MR spec: lipid
necrosis
148
MR spec: lactate
anaerobic metabolism
- N in 1st hr life
- intermediate TE (~140): inversion lactate peak to fix lactate & lipid peak superimposed
149
MR spec: alanine
amino acid in meningioma
150
MR spec: N-acetylaspartate (NAA)
neuronal marker
- super high in canavans
- higher glial tumor grade, lower NAA
151
MR spec: glutamine
- nt
| - (+) w/ hepatic encephalopathy (losing the GLU of your brain!)
152
MR spec: Cr
energy metabolism
| -(-) in tumor necrosis
153
MR spec: Choline (Co)
cell membrane turnover
154
MR spec: myoinositol (mI)
cell volume regulator & byproduct glc metabolism
- (+)-low grade glioma, AD, PML
- (-)-other dementias, high grade gliomas, hepatic encephalopathy
155
Demyelinating vs dysmyelinating
- demyelinating-destroys normal myelin
| - dysmyelinating- disrupts formation & t.o. myelin
156
leukodystrophy
fucked WM in a kid 2/2 lysosomal storage, peroxisomal function or mitochondrial dysfunction
157
Adrenoleukodystrophy (ALD)
- x-linked peroxisomal enzyme deficiency
- parieto-occipital predominance
- "extends across selenium of cc"
- can enhance, restrict
158
Metachromatic
- MC leukodystrophy
- frontal predominant
- tigroid pattern-periVt, deep WM
- u-fbrs spared
159
MC leukodystrophy
metachromatic
160
Alexander Disease
- frontal predominant +/ cerebellum & middle cerebellar peduncle
- can enhance
161
Canavan Disease
- diffuse BL subcortical U fbrs ("subcortical predominance")
| - elevated NAA
162
Krabbe
- centrum semiovale & periVt WM PO predominance
- high density foci in CT (thalamus, caudate, deep WM
- early sparing U fbrs
163
Pelizaeus-Merzbacher
total loss of normal myelination w/ extension to u fbrs
- tigroid (but more classic with metachromatic)
- no enh, no RD
164
head size: ALD, Metachromatic, Alexander, Canavan, Krabbe, Pelizaeus-Merzbacher, Leigh
- Alex & Canavan: big
- Krabbe: small
- the rest N
165
TORCH
CMV (mc), toxo (2nd MC), rubella, HSV
166
CMV
- periVt Ca + polymicrogyria
| - targets germinal matrix
167
toxo
- cats
- BG Ca + hydro
- f (+) in 3rd TM but only causes in 1st 2
168
rubella
- WM vasculopathy/ischemia (T2+)
| - fewer Ca
169
HSV-2
- endothelial cells--> thrombus/hemorrhagic infarct --> emcephalomalacia, atrophy (hydranencephaly)
- unlike adults, doesn't not primarily target limbic system
170
neonatal HIV
- FL atrophy
| - faint BG enhancement precedes BG Ca
171
HIV encephalitis
- 50% aids patients
- CD4 <200
- T2+ symmetric deep WM, spares cortical U fbrs, T1 N
172
Progressive MF leukoencephalopathy (PML)
- JC virus
- CD4 <50
- CT & T1 (-) single or MF asymmetric lesions & involvement cortical U fbrs
- buzzword: "T2/FLAIR (+) out of proportion to ME"
173
BW: "T2/FLAIR (+) out of proportion to ME"
Progressive MF leukoencephalopathy (PML)
174
CMV
- Atrophy,
- periVt hypodensities/T2/FLAIR (+)
* thin ependymal enhancement
175
cryptococcus meningitis
- mc fungal infection in AIDS.
- basilar meningitis
1) non-enhancing dilated perivascular spaces filled with mucoid gelatinous debris,
2) cryptococcoma- T1 (-), T2 (+) lesions in BG, may ring enhance
176
toxoplasma meningitis
MC opportunistic infection in AIDS
- ring enhancing lesions (>1cm) + LOTS of edema
- no RD (atypical abscess)
177
toxoplasma vs lymphoma
- both ring enh
- Toxo=thallium & PET cold, perfusion (-), hem after rx
- Lymphoma= thallium & pet HOT (acts like tumor)
178
Tb meningitis
- basal cisterns, + obstructive hydroceph
- +/- dystrophic Ca, minimal nodularity
- vasculitis--> infarct (kids)
179
HSV (1 in adults, 2 in neonates)
- HSV 1-limbic system
- HSV 2- medial temporal lobe (UL or BL) edema; RD restriction-earliest (diffusion > T2 sens)
- spares bg (distinguished from MCA stroke)
- bleeding (adults > kids)
180
limbic encephalitis
- -paraneoplastic syndroms (from SCLC)
| - HSV app, "negative HSV titer"
181
West Nile
T2+/RD BG + thal.
| +/- hem
182
Creutzfeldt-Jakob Disease-3 imaging appearances
1) RD cortical gyriform-cortex MC early site. +/- BG
2) Hockey stick sgx- BL FLAIR+ dorsal medial thalamus (variant subtype)
3) Pulvinar sgx- BL FLAIR+ pulvinar thalamic nuclei (pst thalamus) (variant subtype)
* rapidly progressive atrophy
183
Creutzfeldt-Jakob Disease-3 types
1) sporadic (80-90%)
2) variant "mad cow"
3) familial (10%)
184
neurocysticercosis
- tinea solium. undercooked pork.
- MC locations desc order-SAS, basal cisterns, parenchyma, Vt
- stages: vesicular--> colloidal--> granular--> calcified/involution
185
Imaging of stages of neurocysicercosis
- stage 1 (vescicular)-cyst + scolex, no enh
- stage 2 (colloidal)-hyperdense cyst, edema + enh
- stage 3 (granular)-early Ca, smaller cysts, less edema/enh
- stage 4 (calcified/involution)- Ca, blooming on SW1
186
leptomeningeal
pial + arachnoid
187
pachymeningeal
Dural.
- Does not extend into sulci
- causes: intracranial hypoTN, dural attachment of meningioma, sarcoid, Tb, Wegener's, fungal infection.
* breast & prostate cancer both deposit solitary dural mets
188
very testable trivia re: infants & meningitis
sterile reactive subdural
189
Rim Phoma
2˚ CNS lymphoma is often extra-axial and can be dural based or fill the subarachnoid space
190
empyema
- Subdural > epidural, (+) complications.
- MCC=frontal sinusitis
- Follow same rules.
191
intracranial abscess
~<10mm
- ring smooth, thicker on O2/GM side, thinner toward WM,
- vs tumor-irregular ring, large
192
abscess-hematog vs direct
hematog > direct
193
cerebritis
early intra-axial inf --> abscess (If not rx)
| -vasogenic edema +/-spotty RD
194
ventriculitis
shunt placement or intrathecal chemo
- fluid fluid levels
- septa--> obstructive hydro
- intraVt abscess extension=deadly
195
MC loc parenchymal contusion
ant TL * inf FL (scrape rough skull base)
196
Grading DAI
- grade 1: GW interface
- grade 2: CC
- grade 3: BS
197
MC locations DAI
- pst cc
| - GM/WM FL & TL
198
imaging DAI
- mult small T2 (+)
| - CT often N
199
SDH vs EDH-"more mass effect than expected for size"
SDH
200
It Be Iddy Biddy Baby Doo-Doo
- hyper acute <24 hr- T1 Iso, T2 B
- acute (1-3 d's)- T1 Iso, T2 D
- early SA (>3d)- T1 B, T2 D
- late SA (>7d)- T1 B, T2 B
- Chronic (>14d)- T1 D, T2 D (center may be T2B)
201
blood on CT-hyperacute acute, acute, SA, chr)
- Hyperacute acute (<1 hr)-hypo
- Acute (1 hr-3 d's)- hyper
- SA (4d- 3 wk)- prg hypo; peripheral rim enh?
- Chronic (>3 wks)- hypo
202
Sequelae of SAH
1) hydrocephalus (early)
2) vasospasm (7-10 d)
3) superficial siderosis-late
203
MCC SAH
Trauma
| -saccular aneurysms 2nd MC (MC idiopathic)
204
Most sensitive MR sequence for SAH. What fake-out to watch out for?
FLAIR (won't suppress)
| -supplemental O2 gives you fake out that looks like SAH on FLAIR
205
What to think of in setting of atraumatic SAH
1) aneurysm (saccular MC)
2) benign non-aneurysm perimesencephalic hemorrhage
3) superficial siderosis
206
benign non-aneurysm perimesencephalic hemorrhage
- blood ant to MB & pons (no lateral ext into Sylvia cistern or IHF) without ID'd aneurysm (95%) (ie: CTA negative).
- etiology NWU: venous bleed?
- pts do well-no rebleed or ischemia
207
superficial siderosis-what is it, classic history and img
- repeated SAH
- "staining on surface with hemosiderin."
- classic img: gradient low signal coating on surface of brain
- sensorineural hearing loss, ataxia
208
pseudo-subarachnoid hemorrhage
Diffuse cerebral edema --> 1) diffuse hypo density 2) compression/collapse SAS (hyperdense)
-~40 HU (acute blood=60-70)
209
Causes intrapenchymal hemorrhage
1) HTN (esp putamen. IV extension)
2) amyloid-dialysis. multiple lobes, different ages
3) SE-numerous small foci RD. BG. surrounding edema, tiny abscesses.
4) other-avm, vasculitis, tumors
210
Where are SE induced abscesses and mycotic aneurysms usually seen
distal MCA
211
intraventricular hemorrhage
usual players
212
ED, SDH causes
- trauma
| - dural & high flow AVMs
213
causes stroke
- ischemia (80%)
| - hemorrhagic (20%)
214
BW: "watershed infarcts in a kid"
moyamoya (idiopathic supraclinoid ICA vasoocclusive disease)
215
What makes a subacute infarct unique?
Enhances without mass effect
216
Fogging
A phase in the evolution of stroke when infarcted brain looks like normal tissue as edema improves (2-3 wks)
-classically with non-con CT, also with T2 MRI (IV contrast would demarcate area of infarct)
217
In what segments of MCA does MCA sign occur?
M1, M2
218
When does stroke ME peak?
3-5 d's
219
Stroke enhancement rule of 3s
starts in 3 days, peaks in 3 wks, gone by 3 mo
220
artery of percheron
vascular variant char by solitary trunk from one of two PCAs to feed rostral midbrain and both thalami (usually there are several BL paramedic arteries org from PCAs)
221
BL paramedian thalamic stroke
artery of percheron
222
structure affected by recurrent artery of heubner stroke
caudate infarct
223
artery of heubner
branch off proximal ACA
| -can get bagged during Acom aneurysm clipping
224
cardioembolic stroke appearance
- multiple foci of RD scattered BL along vascular territories
- clinical history=afib, endocarditis
225
fetal Pcom stroke
infarcts in ant & pst distribution
226
Stroke restricted diffusion time frame
30 mins-2wks
227
stroke phase RD (+), FLAIR (-)
hyper acute (<6 hrs)
228
T1, T2, FLAIR and RD changes throughout stroke.
- 0-6 hrs: RD(+), the rest iso
- 6-24 hrs: T1 (-), T2/F/RD (+)
- 24hrs-1 wk: T1 (-) + bright cortical necrosis, T2/F/RD (+)
229
Hemorrhage transformation-how often does it occur? What is the typical time period? imaging? who gets it?
- 50%
- 6hrs-4d (24 hr with TPA)
- imaging: 1) GM petechia (90%), 2) hematoma (10%)
- anticoagulation, TPA, embolic strokes (esp large), venous infarcts
230
predictors of hemorrhagic transformation in TPA
- multiple strokes
- proximal MCA occlusion
- >1/3 MCA territory
- >6hr since onset delayed recnalization
- no collateral flow
231
venous infracts-causes
* venous occlusion-dural sinus or deep cerebral vein
- babies-dehydration
- older children-mastoiditis
- adults-coagulopathy, OCP
232
MC site venous thrombosis
superior sagittal sinus
233
How often does associated infarct occur with superior sagittal sinus thrombus?
75%
234
empty delta sign
venous thrombus on contrast enhanced CT
235
dense sinus
venous thrombus on non-con CT
236
RF of venous thrombus
heterogenous RD.
237
edema patterns arterial vs venous stroke
- arterial= cytotoxic
| - venous- vasogenic + cytotoxic
238
stigmata of chronic venous thrombosis
development of dural AVF +/or (+) CSF P from impaired drainage
239
ASPECTS
Alberta Stroke Program Early CT Score
- start with 10 pts and lose them based on findings
- MCA, acute ischemia
- >8: good outcome. <7: may CI TPA
240
BD aneurysm sites (AM I Bleeding Profusely?)
* branch points, anterior circulation (90%)
- Acomm 35%
- M1/M2 junction 30%
- ICA/Pcomm junction 30%
- basilar tip-3%
- PICA-2%
241
when do aneurysms rupture?
- size
- pst
- prior SAH
- smoking hx
- F
242
how do locate ruptured aneurysm (in setting of multiple aneurysms)
- sah/clot
- vasospasm
- size
- irregular focal out pouching "Murphy's tit"
243
how often are saccular aneurysms multiple?
15-20%
244
causes of saccular aneurysms?
- idiopathic via congenital deficiency of internal elastic lamina and tunica media at branch points
- smokers, PCKD, CT dl's, aortic CoA, NF, FMD, AVMs
245
aneurysm subtypes
- saccular-branch points, ant circulation
- fusiform-pst circulation
- pedicle aneurysm- artery feeding AVM
- mycotic-distal MCAs
- blister aneurysm=broad based non-branch pt (supraclinoid ICA)
246
fusiform aneurysm associations
- PAN, CT do's, syphillis
- pst circulation
- mimic CPA mass
247
pseudo aneurysm
irregular (often saccular) arterial outpouching at strange/atypical location
-+/- adjacent focal hematoma
248
traumatic aneurysm
often distal secondary to penetrating trauma or adjacent fracture
249
mycotic aneurysm
often distal, MC in MCA
| -hx=endocarditis, meningitis or thrombophlebitis
250
blister aneurysm
- broad based at non-branch point
- MC site=supraclnoid ICA
- sneak, angio often negative
251
infundibular widening
- funnel shaped enlargement at org of Pcomm artery (junction of ICA).
- not a true aneurysm
- no greater than 3 mm
252
pedicle aneurysm
- aneurysm ass with AVM
- found on feeing artery 15%
- hi risk rupture (higher than avm itself) (high flow)
253
Aneurysm rupture trivia-rate/yr, treatment threshold,
- >10mm 1% risk of rupture/yr. Pst circulation higher rate/mm
- 7mm anterior circulation=threshold
254
maximum bleeding sites for Acom, Pcom, MCA trifurcation, basilar tip, PICA
- Acom: interhemispheric fissure
- Pcom: IL basal cistern
- MCA trifucation-sylvian fissure
- basilar tip-interpeduncular cistern, intraVt
- PICA-pst fossa, intraVt
255
what MR artifact can show a basilar tip aneurysm?
ghosting/pulsation-look in PED!
256
normal calcifications
- pineal gland
- habencular-pair of small nuclei located above the thalamus at its posterior end close to the midline
- choroid plexus
- dural Ca
- BG
257
when do you see brain Ca?
- N structures (PG, habencular, CP, dura, BG)
- TS, SW
- infection: cong CMV, Toxo; neurocystercosis
- cavernoma
- avm
- tumors: OD, ED, AC, GB, Meningioma, CP, OS
258
Old Elephants Age Gracefully
intracranial tumors that calcify (that people talk about: OD, ED, AC, GB
259
timing of post SAH vasospasm
4-14 d's
260
What does vasospasm look like?
-smooth long segments of stenosis involving multiple vascular territories--> stroke
261
who gets post SAH vasospasm?
Fisher score: >1 mm or intravt/parenchymal extension
-larger=more risk
The Fisher scale is the initial and best known system of classifying the amount of subarachnoid hemorrhage on CT scans, and is useful in predicting the occurrence and severity of cerebral vasospasm, highest in grade 3 2.
262
non-SAH causes vasospasm
meningitis, PRES, migraine headache
263
crescent sign
T1(+) intramural blood in dissection
264
Associated dissected neck vessels in penetrating vs blunt trauma
- penetrating-carotids
| - blunt-vertebrals
265
NASCET
North American symptomatic carotid endarterectomy Trial
-evaluated extra cranial ICA
- maximum ICA stenosis (A) compared to parallel (non-curved) segment of distal cervical ICA (B)
- formula: (1-A/B) x 100= % stenosis
- CEA >50%
266
MC systemic vasculitis to involve CNS?
PAN (late finding)
267
MC collagen vascular disease to involve CNS?
SLE
268
1˚ CNS vasculitis
1˚ angiitis of CNS (PACNS)
269
2˚ CNS vasculitis from infection (or sarcoid)
Meningitis (bacterial, Tb, Fungal), SE, Sarcoid
270
systemic vasculitis with CNS involvement
PAN, Temporal arteritis, Wegeners, Takayasu
271
CNS vasculitis from systemic disease
cocaine, RA, SLE, Lymes
272
appearance of CNS vasculitis
- multiple areas of vessel narrowing + dil (beaded)
| - focal vascular occlusion
273
Moya Moya-patho, img, who
- non atherosclerotic stenosis of supraclinoid ICA --> occlusion --> progressive stenosis, enlargement of lenticulostriate a's (puff of smoke)
- watershed distribution
- sickle cell, NF, radiation, DS
- bimodal age distribution (early childhood: stroke, middle age: bleed)
274
BW: "puff of smoke"
Moya moya angiographic appearance
275
Crossed cerebellar diaschiasis (CCD)
- corticopontine-cerebellar pathway connecting cerebral hemisphere to opposite cerebellar hemisphere
- pathway disrupted by tumor, radiation, etc--> decreased metabolism. problem is in the cerebrum!
- cross-crossed appearance of hypo metabolism on FDG-PET
276
dolichoectasia of basilar artery
widened elongated twisty appearance of basilar artery, probably result of chronic HTN (abN vessel remodeling)
- Smoker criteria for severity: height, laterality
- complications: none, dissection, compression CNs, stroke, HCP
277
Things that RD
- stroke
- bacterial abscess, cjd, herpes
- epidermoids, hyper cellular brain tumors (lymphoma)
- acute MS lesions
- oxyhemoglobin
- post ictal states
- artifacts (susceptibility and t2 shine through.)
278
Why do things enhance in the brain?
1) extra-axial
| 2) break down BBB
279
Signs of extra-axial location.
1) CSF Cleft-one of most reliable.
2) displaced subarachnoid vessels-interposed btw mass & brain. Vessels=flow voids.
3) cortical GM btw mass & WM
4) Displaced, expanded SAS
5) broad dural base/tail
6) bony reaction
280
how to differentiate btw mets and infection?
infection RD
281
MC location metastasis for adult vs kid
- adult-supratentorial GW junction (blood flow)
| - kids- neuroblastoma (bones, dura, orbit-not brain!)
282
common met morphology
round, spherical
283
% mets solitary vs multiple?
25-50%/50%
284
Bleeding mets-MR CT
melanoma, renal, carcinoid/choriocarcinoma, thyroid
285
MC intra-axial mass in adult
met (next step: look for primary)
286
met vs 1˚ re: edema
met more edema
287
1˚ brain tumors that like to be multiple
- lymphoma, multicentric GBM, gliomatosis cerebri
| - from seeding: MB, Epend, GBM, Oligodendroglioma
288
Syndromes associated with tumors
*tumors in syndromes more likely to be MF
1) NF1-optic gliomas, astrocytomas/gbms
2) NF2-BL schwannomas, meningiomas, ependymomas, dermoid cysts
MSME: multiple schwannomas, meningiomas, ependymomas
3) TS-subependymal tubers, IV giant cell astrocytoma
4) VHL-hemangioblastomas (brain, retina)
5) Nevoid basal cell syndrome (Gorlin)-MB
6) Turcot-GBM, MB, Intestinal polyposis
7) Cowdens-lhermitte-duclos (dysplastic cerebellar gangliocytoma)
289
cortically based tumors
*most intra-axial tumors are in WM. Not much edema (sm ones can be missed.)
-PDOG:
Pleomorphic xanthoastrocytoma (PXA)
Dysembryoplastic Neuroepithelial Tumor (DNET)
Oligodendroglioma
Ganglioglioma
290
PXA (pleomorphic xanthroastrocytoma)
- peds (10-20 yo)
- always supratentorial, TL
- cyst w/ nodule (50%)
- Enh. No peritumoral T2. Dural tail. Invades leptomeninges
- just like DNET but not an infant
291
DNET (dysembryoplastic neuroepithelial Tumor)
- hx: seizure resistant to drugs. <20 yo
- TL
- focal cortical dysplasia-80%
- CT-hypodense
- MR: T2 (+) BUBBLY w/ bright FLAIR rim
- bright rim sign: persistent rim of FLAIR signal
292
Oligodendroglioma
- grade II presenting as slow-growing cortical/subcortical mass (vs other gliomas that mainly off WM)
- 40-50 yo
- FL
- Ca 90% ("ribbon Ca.") Enh. EXPANDS CORTEX.
- 1p/19q deletion
293
Ganglioglioma
- any age (13 yr old w/ seizures)
- anywhere (usually TL)
- look like anything (cystic &. solid + focal Ca). Enh. Not bubbly.
294
intraVt tumors
- From wall/sp:
- ependymoma
- MB
- SEGA
- SubEpend
- central neurocytoma
- from CP
- CP papilloma
- CP carcinoma
- Xanthogranuloma
- Misc
- mets
- meningioma
- colloid cyst
295
Ependymoma-what, who, where, img
-intraVt tumor w/ bimodal (larger peak ~6 yo)
- 2 flavors:
1) floor of 4th Vt (70%)-toothpaste (For of Luschka/Magendie--> basal cisterns)
2) Sup Tent (30%)-big, >4 cm
-enhance heterogeneous, Ca 50%
296
Medulloblastoma
- PNET tumor. MC
- bimodal (large peak ~10 yo)
- roof 4th vt --> into 4th vt, no basal cistern effacement
- hyerpdense, enh homog, Ca 20%, RD+
- met fvia CSF (drop mets + Zuckerguss/leptomeningeal enh)
297
BW: zuckerguss
German for "sugar icing", leptomeningeal carcinomatosis seen on post contrast imaging of brain and sc.
298
What is medulloblastoma ass with?
- Basal cell nevus syndrome (Gorlin syndrome)
| - Turcots Syndrome
299
Gorlin syndrome
- thick dural calcs
- basal cell skin cancer after radiation (ass w/ MB)
- odontogenic cysts
300
next step if you see pst fossa neoplasm?
preoperative imaging of entire spine
| *tumor spread statistically significant predictor of outcome
301
Subependymal Giant Cell Astrocytoma (SEGA)
- 11 yo TS.
- lateral wall LV (near FOM) --> HCP
- enh homog
302
SEGA vs Subependymal Nodule (SEN)
SEN stable and found anywhere along lateral Vt. Both calcify.
303
Subependymoma
- adult
- well circumscribed non enhancing mass in FOM & 4th Vt --> HCP
- T2 (+) (like most tumors)
304
Central neurocytoma
- most common IV mass in adult (20-40yo)
| - "Swiss cheese"-numerous cystic spaces (T2+) + Ca
305
choroid plexus papilloma
- Peds (85%)-LV trigone. Adults (15%)-4th Vt
| - make up ~15% tumors in kids <1yo
306
Which tumor(s) is the exception to the general rule of thumb that tumors are pst fossa in peds?
choroid plexus origin (Crazy bc reversed)
307
choroid plexus CA
- only in kids (ie: LV trigone)
- Li-Fraumeni syndrome (p53)
- choroidal arteries shunting blood to tumor on angiography
- +/- CSF dissem (usually solitary)
308
Xanthogranuloma
adult benign choroid plexus mass
RD+
These lesions represent desquamated epithelium into the lumen of choroid cysts within the choroid plexus. As a result, cholesterol/lipid-rich content of epithelial cells accumulates, sometimes combined with blood products, and results in a xanthomatous response, as this material is ingested by mononuclear cells.
309
What's the MC location & 1˚ of intraVt metastasis?
```
LV trigone (vascular supply of choroid)
-Lung (more common in general), but renal goes more often. ie: depends on how question is worded.
```
310
colloid cyst
- anterior 3rd vt bind FOM
- img: rounded, hyperdense
- cholesterol: T1+, T2-
- no cholesterol: T2+
311
mass in LV trigone <10 yo & >40 yo
<10 yo:
choroid plexus papilloma
>40 yo:
1) met
2) lymphoma
3) meningioma
312
cerebellar pontine angle masses
1) vestibular schwannoma 75%
2) meningioma 10%
3) epidermoid 5%
313
is meningioma MC in men or women
women (one of the few)
314
which tumor may widen the pores acoustics?
schwannoma (trumpet shape, ice cream cone)
315
which nuc medicine scans are positive in meningioma?
ocreotide & Tc-MDP
316
what tumor does radiation to the head cause?
meningioma
317
mc location meningioma
cerebral convexity
318
meningioma vs schwannoma
- meningioma-enh homog, don't usually invade IAC, Ca
| - schwannoma-enh less homog, invade IAC, less Ca
319
Causes epidermoid cyst
congenital or acquired (trauma)
320
MC location dermoid cyst
suprasellar cistern --> pst fossa
| *midline (vs epidermoid)
321
BW "chemical meningitis"
ruptured dermoid.
322
Ruptured dermoid-MCC, syx's, and Aunt Minnie appearance ruptured dermoid
- spon't (MC). Trauma
- headache and seizure
- fat droplets floating in Vts or SAS
323
arachnoid vs epidermoid cysts
EC=FLAIR (+), RD(+)
324
Arachnoid cyst
- SAS containing CSF
- (+) in mucopolysaccharidoses
- FLAIR (-), RD (-)
325
atypical teratoma/rhabdoid tumor (AT/RT)- who, where, img appearance
- WHO IV
- ~2yo
- Cerebellar (can be supratentorial), hetero/necrotic + Ca
326
medulloblastoma vs atypical teratoma/rhabodid tumor
both WHO grade 4. AT/RT worse
- AT/RT-2 yo; MB 6 yo
- AT/RT Ca, MB doesn't
327
BW: "increased head circumference"
Atypical teratoma/rhabdoid tumor
328
juvenile pilocytic astrocytoma (JPA)
WHO I astrocytoma in kids
- cerebellum > supratentorial
- cyst w/ nodule, nodule & wall enh
- + optic tract in NF 1 (pst fossa JPAs not ass with this)
329
what tumor is the exception that infratentorial tumors are pediatric?
hemangioblastoma
330
hemangioblastoma-who, where, img, ass
- cerebellar nodule in cyst in ADULT. No wall enh (vs JPA)
- multiple?-von Hippel Lindau
- slowly growing --> HCP
- vascular (peripheral FVs)
- ass w/ poycythemia
331
what is hemangioblastoma ass with?
- VHL
| - polycythemia
332
diffuse pontine glioma
- 3-10yo, high grade fibrillary glioma in pons
- T2+, subtle/no enh. 4th vt flattened
- img findings= classic --> no biopsy needed
333
supratentorial adult tumors
astrocytoma, oligodendroglioma (better prognosis)
| -IDH mutation
334
astrocytoma subtypes
-Grade 1 (SEGA, pilocytic astrocytoma)
-grade 2 (low grade astrocytoma, gliomatosis cerebri) (diffuse)- Diffuse T2 at site of tumor, ME, ø enh
-grade 3 (anaplastic): T2/FLAIR mismatch sgx. mild enh.
- grade 4 (GBM): ring & heterog enh. T2/FLAIR+. cross midline
- IDH+ 10%: younger, better prognosis, 2˚ (from progression of previous lower grade)
-IDH(-): older, worst prognosis, 1˚
335
ribbon pattern calcification
oligodendroglioma
336
WHO grade classification. Which tumors are the exception?
- grade 2- low grade, no enh
- grade 3-mild int
- grade 4- intense enh
* exception Pilocytic astrocytoma (enhancing nodule), SEGA (bc IVt)
337
GBM associations
- Turcot syndrome (GI polyps)
- NF 1
- Li Fraumeni syndrome
338
T2/FLAIR mismatch sign
T2 bright, FLAIR iso (only a bright rim)
| Astrocytoma grades 2 & 3.
339
Grade 2 astrocytoma
"Diffuse"
- prefers WM
- T2/FLAIR mismatch sgx (bright on T2, hypo on FLAIR)
- no enh
340
Grade 3 astrocytoma: name, img
"anaplastic"
- prefer WM
- T2/FLAIR mismatch sgx
- mild enh
341
Grade 4 Astrocytoma
"GBM"
- prefers deep WM
- ring & heterog enh
- T2/FLAIR+
- cross midline. 25% MF
- central locations (like thalamus) worse than normal
- IDH+ 10%: younger, better prognosis, 2˚ (from progression of previous lower grade)
- IDH(-): older, worst prognosis, 1˚
342
gliomatosis cerebri
diffuse low grade glioma
- at least 3 lobes, BL
- blurring GW differentiation on CT
- T2++
- no enh (low grade)
343
met vs GBM
- met: irregular ring enh, MF > UF, GWM junction
| - GBM: spherical ring enh, UF > MF, deep WM
344
1˚ lymphoma-types (HL vs NHL), who, ass (virus), img
- non-hodgkin bcell in end-stage AIDS, post transplant.
- EBV+
- intensely enhancing homogenous solid mass in periVt region ("rim phoma"), RD+, thallium+, PET+
345
"rim phoma"
- Thick, irregular periventricular/ependymal enhancement seen in lymphoma
- vs ependymitis (ex: CMV)-thin, smooth & linear
346
desmoplastic infantile ganglioglioma/astroctyoma "DIG"
- who 1; -<1 yo
- large, cystic + hydro
- always supratentorial (FL, PL)
347
supratentorial tumors in peds
DNET
PXA
DIG
348
BW: rapidly increasing head circumference
desmoplastic infantile ganglioglioma
349
chordoma
- locally aggressive notochord tumor of midline
- sacrum > clivus > C2 (--> ds --> adj VB)
- T2+
T1
intermediate to low-signal intensity
small foci of hyperintensity (intratumoral hemorrhage or a mucus pool)
T2: most exhibit very high signal
T1 C+ (Gd)
heterogeneous enhancement with a honeycomb appearance corresponding to low T1 signal areas within the tumor
greater enhancement has been associated with poorer prognosis 11
SWI/GE: variable intralesional hemorrhage, suggested by the presence of blooming artefact
DWI/ADC
conventional chordoma: 1474 ± 117 x 10-6 mm2/s 13
dedifferentiated chordoma: 875 ± 100 x 10-6 mm2/s 13
350
chondrosarcoma
- lateral
| - T2(+) + arcs & rings
351
hemangiopericytoma
soft tissue sarcoma that can mimic aggressive meningioma (bc both enhance homog) BUT no Ca or hyperostosis
-does invade skull.
352
pituitary adenoma-, what pt of pit, img
- adults (97%). More syx's in women
- micro <10mm, form in adenohypophysis (ant 2/3). Macro >10mm
- T1/T2 (-), takes up contrast slowly (enh less than N pituitary)
353
pituitary apoplexy-causes, img, mx
- hemorrhage or infarction of pituitary into enlarged gland (2/2 pregnant or macro adenoma)
- bromocriptine (PL drugs)
- sheehan syndrome (post party)
- cerebral angiography-T1+ (vs adenoma)
- emergent (low BP)
354
lesions in sella/parasellar region
- adenoma. (T1/T2 -)
- apoplexy-T1+
- rathke cleft cyst- cystic, ie: T2+
- epidermoid
- craniopharyngioma
355
rathe cleft cyst-origin, app (enh?)
-ectodermal
-cleft btw ant & pst pituitary
-T2+++
-no enh
356
craniopharyngioma
a) papillary-10%, adults (Papi for Pappi)
| b) adamantinomatous- 90%, (Ad for adol)
357
papillary craniopharyngioma
- adults (papi for pappi)
- less recurrence (encapsulated)
- along infundibulum
- enh+
- no Ca
358
adamantinomatous craniopharyngioma
- pediatrics
- Ca
- T1/T2+
- enh+
359
hypothalamic hamartoma-what/where is it, img, classic hx
Aunt minnie for hamartoma in tuber cinereum (pt of HT btw mamm bodies & optic chasm)
- T1/2 iso, no enh
- classic hx: galactic seizures (precocious puberty MC)
-galactic seizure= rare type of seizure that involves a sudden burst of energy, usually in the form of laughing.
360
buzzword: "machinery oil"
adamantinomatous craniopharyngioma
361
pineal region tumors
1) germinoma-MC
2) pineoblastoma
3) pineocytoma
4) pineal cyst
* dorsal Parinaud syndrome-vertical gaze palsy)
362
Pineal Germinoma
- exclusively boys (suprasellar MC in girls)
- mass w/ fat + Ca ("engulfed Ca") --> heterosexual T1, T2, variable enh
- hCG--> precocious puberty
363
pineoblastoma
- occur in kids (vs pineocytoma)
- highly invasive
- hetero, enh+++, expanded Ca pattern
- ass w/ retinoblastoma ("trilateral")
364
pineocytoma
- rare in childhood
- well-circumscribed & non-invasive
- more solid (enh+++)
- expanded Ca pattern
365
pineal cyst
incidental
| 25% Ca
366
midline crossing
- GBM, lymhoma
- radiation necrosis
- MS plaque in cc
- meningioma of falx
367
T1 bright tumors (bc most are dark/intermediate! exc if tumor bled)
-fat-dermoid, lipoma
-melanin-melanoma
-blood-bleeding met/tumor
MRCT-melanoma, renal, chorioCA, thyroid
pituitary apoplexy
-cholesterol- colloid cyst
368
Lhermitte-Duclos/Dysplastic Cerebellar Gangliocytoma
- hamartoma
- tiger stripe mass in 1 cerebellar hemisphere (occasionally causes vermis)
- associated with Cowdens syndrome & breast cancer--> mammogram
369
Cowden Syndrome
- aka multiple hamartoma syndrome
| - char by multiple hamartomas throughout body & increased risk of several cancers
370
MC type of high flow vascular malformation
high flow AVM
371
AVM vs Dural AVF
- AVM is high flow, congenital and has nidus.
| - Dural AVF is variable flow, acquired (dural sinus thrombosis) and no nidus.
372
Symptom of high flow AVM
```
#1 HA
#2 Seizure
```
373
Symptom of dural AVF
tinnitus (esp if signmoid sinus involved)
374
Risk of AVM bleed
* bleeding MC complication (3% annual)
- smaller AVM (higher P)
- smaller draining vein (can't reduce P)
- perinidal aneurysm
- BG location
375
Imaging high flow AVM
- supratentorial (usually)
- a --> nidus --> v
- adjacent brain may be gliotic (T2+) & atrophic
- wedge-type configuration is typical
- "pedicle aneurysm"
376
Imaging dural AVF
- no nidus
- transosseous vascular channels/perforating vess
- can be occult on MRI/MRA-catheter angio if high suspicion
377
What increases the risk of a dural AVF bleed
direct cortical venous drainage
378
developmental venous anomaly (DVA)
-how to differ from cavernoma
-what happens if you resect it?
- Congenital variation in normal venous drainage associated with cavernous malformations (never bleed in isolation-if see evidence of prior bleed/blooming on GRE, probably have associated cavernoma)
- resection :( --> venous infarct
379
imaging DVA
"Caput madusa"-enlarged umbrella like collection of enlarged medullary (WM) v's
- "Large tree with multiple small branches"
- collection of vessels converging towards enlarged v (seen on venous phase only)
- +/- T2+ gliosis
380
cavernous malformation/cavernoma/cavernous angioma: what is it, causes
- low flow, benign vascular hamartoma containing immature bv's and no intervening normal brain tissue; possibly 2/2 radiation
- small ooze, nothing catastrophic. Intralesional bleeds diff ages
381
imaging cavernoma
- "popcorn-like" with "peripheral rim of hemosiderin"
- locules w/ blood at different stages of evolution (F/F level suggests recent)
- GRE
- +/- associated DVA
- solitary or multiple (mc in hispanics)
- sm or large
382
capillary telangiectasia-what, cause, sig, common sites, img
- low flow cluster of enlarged, dilated capillaries interspersed with normal brain parenchyma
- can be 2/2 radiation
- incidental. usually don't bleed.
Imaging
General features
Common sites: Pons, cerebellum, spinal cord
Usually < 1 cm
CT
Usually normal
MR
T1 usually normal
T2
50% normal on T2
50% show faint stippled foci of hyperintensity
Large BCTs may show ill-defined FLAIR hyperintensity
Moderately hypointense on GRE; profoundly hypointense on SWI
T1 C+ shows faint stippled or speckled brush-like enhancement
Large BCTs typically contain prominent linear draining vein(s)
383
imaging capillary telangiectasia
- brush like, stippled pattern of enhancement
- solitary lesion in the pons
- GRE
384
Habenular calcification-what, ass
- curvilinear structure e~mm ant to pineal body normally calcified in 1/5 adults.
- trivia: (+) ass w/ schizophrenia
385
choroid plexus locations
- pia mater
-Roof of 3rd ventricle, body & temporal horn of lateral ventricle via choroidal fissure, inferior roof of 4th ventricle
- all ventricles except F/OLs and cerebral aquaduct.
386
Is pineal gland calcification common?-what should you think of in kids
In adults. Rare in kids (geminoma, pineoblastoma or pineocytoma)
387
"Engulfed" Ca pattern of pineal gland
germinoma
388
"expanded" Ca pattern of pineal gland
pineoblastoma & pineocytoma
389
name that syndrome: basal cell carcinoma and odontogenic keratocysts
Gorlin Syndrome
390
What part of BG does Ca favor?
globus pallidus
391
extensive, symmetric BG Ca
Fahr disease
392
types of mixed vascular malformations
1) DVA + AV shunt
2) DVA + telangiectasia
393
bright rim sign
persistent rim of FLAIR signal char of DNET
394
intracranial vascular anomalies to consider
- AVM
- dural AVF
- cavernous
- developmental venous anomaly
- capillary telangiectasia
395
vascular malformations with and w/o shunting
- with: AVM, dural AVF, pial AVF, vein of galen aneurysmal malformation
- w/o-developmental venous anomaly, sinus pericranii, cavernous malformation, capillary telangiectasia
396
AVM grading system
Spetzler Martin
397
meningeal hemangiopericytoma
aggressive form of solitary meningioma
- large, hetero + dural tail
- stat6 and CD34+
- (+) risk recurrence
398
MS locations (4 total)
1. juxtacortical/intracortical
2. periVt
3. infratentorial
4. spinal cord
399
multinodular and vacuolating neuronal tumor-where, appearance, pres, who, mx
- Small 'bubbly' indolent subcortical tumors
- young/middle-aged adult with new onset seizure
- These tumors have been most frequently identified in the temporal lobe, although that is likely to be due to that location being more likely to result in seizures than necessarily a predilection for that lobe
- type of glioneuronal and neuronal tumors
- T2/FLAIR+, T1-, usually enh(-)
- mx: MVNTs appear to be benign tumors with very indolent biological behavior which can, if asymptomatic, be followed by imaging alone. In symptomatic patients (where the MVNT is causing seizures) surgical resection often controls seizures, with no tumor regrowth reported
