Neuro- iphone Flashcards
Ddx restricted diffusion
Infarct Abscess/empyema Epidermoid cyst DAI Sz/status Encephalitis Densely cellular tumor (mening, sm blue cell) PRES (rarely, = infarct) CJD MS Osmotic demyelination Hypoglycemia Wernicke's
T1 bright (6 things)
Fat Proteinaceous fluid Subacute hemorrhage (methemoglobin) Melanin Gd Ca (rarely)
Causes of susceptibility artifact on GRE/SWI
air hemorrhage (methemoglobin, deoxyhemoglobin) calcium metal (others?)
MR evolution of stroke:
Acute infarct vs.
Subacute infarct vs.
Old lacunar infarct vs.
Virchow-Robin
Acute:
Restrict diffusion +/- mild T2/FLAIR edema
Subacute:
ADC normalizes before DWI, typically by one week (then DWI nL by 2 wks?). Also, FLAIR increases as ADC normalizes. Look for e/o laminar necrosis with high T1 signal and hallmark gyriform enhancement @ 1-2 wks (also hyperdense & enhancing on CT). May also see petechial hemorrhage (high T1 methemoglobin).
-May see enh at 3 days-3 wks
Chronic lacune:
T2 & FLAIR bright, no diffusion abnormality
VR:
T2 bright only, normal FLAIR
Ddx of ischemic stroke in kids
Congenital heart dz Blood dyscrasias Meningitis Arterial dissection Trauma ECMO Venous thrombosis
Ddx of ischemic stroke in young adult
Cardiac emboli Athero Drug abuse Arterial dissection Coagulopathy Vasculitis Venous thrombosis
Ddx of ischemic stroke in elderly
Athero Cardiac emboli Coagulopathy Amyloid Vasculitis Venous thrombosis
Causes of non-traumatic ICH
#1 overall- HTN #1 in elderly- CAA #1 in kids- vascular malformation
Other causes:
- Hemorrhagic transformation of ischemic stroke, esp venous (look for underlying tumor)
- Aneurysm
- CA
- Coagulopathy
Shape & Common sites of HTN hemorrhage
-Typically ovoid in shape
Basal ganglia
Thalami
Cerebellum
Pons
Sometimes in lobar WM (less specific)
-Look for assoc sign of chronic uncontrolled HTN (i.e. punctate GRE microbleeds/old hemorrhage in same dist, wm dz on FLAIR, lacunes)
Common sites of Cerebral amyloid angiopathy-related hemorrhage
Lobar
Cortical
Cortical-subcortical
-Look for assoc signs of CAA (multiple GRE microbleeds in peripheral cortical distribution/old bleeds, wm dz)
DAI on CT
Small petechial hemorrhages (or hypodensities) at SC GW jcn or CC
Vascular malformations: hemorrhagic vs. NON
Hemorrhagic:
- AVM
- Cavernoma
NON-hemh:
- DVA
- Capillary telangiectasia (pons)
Places to look for SAH
- interpeduncular cistern
- dependent portions of ventricle
- sulci (by quadrant)
- r/o hydrocephalus… if any enlargement of temporal horns, this is an emergency! Be careful, b/c easy to miss synmetric enlargement!
Common sites for aneurysm
Branch points:
- Acomm
- Pcomm
- basilar tip
- MCA trifurcation
- PICA origin
Tumors more prevalent in women
Meningioma (4:1)
Neurofibroma
Pineocytoma
Pituitary tumor
Tumors more prevalent in men
Pineal germinoma (10:1) Pineal parenchymal tumor (4-7:1) Medulloblastoma (3:1) GBM (3:2) Choroid pelxus papilloma (2:1) CNS lymphoma Hamartoma of the tuber cinereum
Hemorrhagic tumors
GBM most common
Mets #2 (RCC, thyroid, chorio, melanoma)
Oligodendroglioma (#2 primary)
2 primaries, 4 mets
Intra-axial lesions w marked edema (6)
(“MARGHL” mneumonic)
Mets Abscess Radiation necrosis GBM Hematoma (mild) Lymphoma (?mild)
Ring-enhancing lesions
MAGIC(L)-DR: --------------------- M ets A bscess G BM I nfarct (subacute) C ontusion L ymphoma (rarely, AIDS) D emyelinating dz (incomplete rim) R adiation necrosis ... OR ... Resolving hematoma
Distinguishing ring-enhancing lesions on MR:
- Abscess
- GBM
- Mets
- Demyelinating dz
- Resolving hematoma
Abscess:
- thin uniform enh (and low T2) rim, RESTRICT DIFFN, can be multiple w daughter cyst
- bacterial if central DWI, fungal if peripheral nodular DWI
- toxo if HIV+, peripheral, DWI neg, can be mult
GBM:
-nodular thick wall, HEMH, low DWI signal
Mets:
-thick walled, often multiple, h/o 1o CA, DWI neg, some can hemh
Demyelinating dz:
-incomplete rim, often multiple
Resolving hematoma:
-h/o trauma, T1/T2/GRE changes from blood products
Calcified GLIAL tumors
O ligodendroglioma (70-90%)
E pendymoma (44%)
A strocytoma (low-grade only, 10-20%)
[G BM rarely! Suggests degen of low-grade tumor]
Notes:
- a calcified intracial tumor is most likely to be an astrocytoma since they are much more common, even though almost all oligodendrogliomas calcify
- these are all glial tumors, other tumors also calcify
Other calcified tumors
Extra-axial:
- Meningioma
- Craniopharyngioma
- Chordoma
Intra-axial:
- Mets
- Choroid plexus papilloma
Common intra-axial mets
lung (extra too)
breast (extra too)
melanoma (can be hemorrhagic)
colon
Common extra-axial mets
breast (also intra)
prostate
lung (also intra)
neuroblastoma
Common hemorrhagic mets
melanoma
RCC
thyroid
chorio
** CAREFUL on GRE, some mets can be GRE+ due to Ca (e.g. colon)!!
Congenital brain tumors (< 60 days old)
Teratoma #1 by far (1/3-1/2), most are supratentorial (2/3)
PNET (primitive neuroectodermal tumor): curvilinear, sparse Ca Astrocytoma Choroid plexus papilloma Ependymoma Medulloepithelioma Germinoma Angioblastic meningioma Ganglioglioma
Most common location for intracranial neoplasm in kids
Posterior fossa
Posterior fossa masses in children (in order of freq w typical location of each)
1: Medulloblastoma- vermis (think Midline), restricts diffusion
Brainstem glioma- us. astrocytoma
Choroid plexus papilloma- 4th ventricle
CPA masses
Consider these all as p-fossa masses!!
A coustic (or vestibular) Scwhannoma ** #1 most common (80%)
M eningioma
E pendymoma
N euroepithelial cyst (arachnoid or epidermoid)
Ddx cerebellar lesion in ADULTS
-Mets
…or…
- Hemangioblastoma (= most common 1o):
- predominantly cystic w small nodule
- assoc w VHL
-also remember AMEN for p-fossa!
Intraventricular masses (top 3)
#1- Choroid plexus papilloma #2- Ependymoma #3- Subependymoma
central neurocytoma SEGA (subependymal giant cell atrocytoma) all other astrocytomas meningioma colloid cyst choroid plexus CA mets
Most common lateral ventrical mass @ foramen of Monro
SEGA
Pilocytic astrocytoma
Both w typical age 10-40 yo
Most common lateral ventrical mass @ body, according to age
0-10:
PNET (primitive neuroectodermal tumor)
Teratoma
Choroid plexus papilloma
10-40:
Ependymoma
Pilocytic astrocytoma
Central neurocytoma
> 40:
Subependymoma
Most common lateral ventrical mass @ trigone, according to age
0-10:
Choroid plexus papilloma
> 40:
Meningioma
Mets
Masses of anterosuperior 3rd ventricle
Colloid cyst Meningioma Choroid plexus papilloma Hamartoma Glioma Vascular lesion Granulomatous dz
Pineal region masses
3 main groups:
- Germ cell tumors: ** ~60%
- germinoma (young male)
- teratoma
- embryonal sinus tumor
- choriocarcinoma
- Germ cell tumors: ** ~60%
- Pineal parenchymal tumors: ~14%
- pineocytoma (adults)
- pineoblastoma (kids) - Others:
- pineal cyst
- glioma
- meningioma (tentorial)
- Vein of Galen malformation
- arachnoid cyst
- lipoma
Suprasellar masses
S ella (pituitary) tumor
S arcoid
A neurysm
A rachnoid cyst
T eratoma
C raniopharyngioma
H ypothalamic gliomatoma
H amartoma of tuber cinereum
H istiocytosis
Meningioma
Mets
Optic nerve glioma
Craniopharyngioma vs Rathke’s cleft cyst
Both can be cystic
- CP enhance (think CP = C+), can Ca+
- Rathke’s have mural nodule, do NOT enhance
1o vs 2o CNS lymphoma
1o- periventricular, CC, homog enh, almost all B-cell
2o- us meningeal
Epidermoid vs. Dermoid:
- freq
- peak age
- germ cells
- location
- imaging
Epi. Dermoid
Freq: epidermoids more common
Peak age: 40-50 vs 20-30
Germ cells: ectoderm vs ecto+meso
Location: off midline (CPA, parasellar, p-fossa) vs midline (pericerebellar, suprasellar)
Imaging: follows CSF & restr diffn vs fat
DDx for intradural intramedullary spine lesion
- demyelinating dz (MS, transverse myelitis, NM optica aka Devic’s, adem?)
- contusion
- infarct
- syringohydromyelia
Masses: ependymoma (myxopapillary vs ?cellular) astrocytoma hemangioblastoma lipoma/epidermoid/dermoid AVM Rarely mets Rareel abscess
Ddx for intradural extramedullary spine mass
meningioma schwannoma/neurinoma neurofibroma hemangiopericytoma lipoma/epidermoid/dermoid arachnoid cyst/adhesion drop/lepromeningeal mets veins or AVM pulsation artifact!!
DDx for extradural spine mass
Degen:
- herniated disc
- synovial cyst
- osteophyte
- rheumatoid pannis
Non-degen:
- mets
- abscess
- hematoma
- 1o tumor (expansion or invasion)
- epidural lipomatosis
Osteomyelitis vs Modic type I changes vs Tumor infilatration
-Sometimes cannot tell since all endplates are T1 dark, T2 bright!
- compare to priors
- look for 2o signs of infection with prevertebral ST edema/enhancement extending above and below level
- if disc is dark on T2, can r/o discitis
- tumors restrict diffusion, us single level, us ST & discs spared
Clivus lesions
1 Mets
Chordoma (midline, min enh)
Plasmacytoma
Chondrosarcoma (more lateral)
Meningioma Petrous apicitis (Gradenigo syndrome, CNopathies)
Carotid space masses
Reactive LN
Met LN (us necrotic CCA)
Paraganglioma (carotid body ?if split ICA/ECA, or glomus vagale)
Schwannoma (thick nod rim enh, cystic centrally)
Neurofibroma
Lymphoma
Mets (rare)
Lesions that cross corpus callosum
GBM CNS lymphoma (can infiltrate BG/brainstem too!) MS DAI Gliomatosis
Splenium: DAI Viral infx Sz meds? ADEM Marchidava-Bignami (EtOH)
PML
Adrenal Leukodystrophy
Lipoma(?)
AVM(?)
Classes of WM diseases
- Primary demyelination
- Ischemic demyelination
- Infection-related demyelination
- Toxic and metabolic demyelination
- Dysmyelination (leukodystrophy)
Diseases of Primary demyelination
MS (periventricular, juxtacortical, rarely cortical, spares BG [vs ADEM], incomplete ring enh highly specific)
Diseases of Ischemic demyelination [and pattern]
- chronic small vessel ischemic disease [scattered]
- infarction (thromboembolic, lacunar, and deep WM)
- vasculitis (incl lupus and sarcoid) [scattered]
- drug-induced vasculopathy [convexities]
- dissection
- migranous ischemia
- moyamoya [scattered]
- anoxic
- CADASIL [a-temporal, m-fronal, ext capsule]
?isch
-PRES (cortical & subcortical, posterior predominance, can progress to infarct and restrict diffn)
Infection-related demyelination
- PML [U-fibers, no mass effect or enh]
- HIV [early diffuse hazy T2 wm changes]
- ADEM [monophasic numerous WM/BG patches, all enh, may also involve cortex, brainstem/p-fossa/cord]
- SSPE
- Lyme
- Neurosyphilis
Diseases of toxic or metabolic demyelination
- Osmotic demyelination (formerly central pontine, but can also affect thalami, BG, & WM)
- Wernicke-Korsakoff (med thal, other areas)
- Radiation injury [confluent, U-fibers]
- Necrotizing leukoencephalopathy
- Marchiava-Bignami disease (CC esp genu & splenium)
- Delayed post-hypoxic leukoencephalopathy (confluent wm, restricted diffn, rapidly progressive)
Diseases of dysmyelination
- Metachromatic Leukodystrophy [diffuse, “tigeroid” appearance of wm, most common]
- Adrenal Leukodystrophy [symmetric occ & splenium CC]
- Leigh Disease [focal SC & deep GM, incr lactate peak]
- Alexander Disease [frontal]
- Canavan Disease [diffuse +/- cortical GM, marked NAA peak]i
Alzheimer disease
parietotemporal atrophy (out of proportion to WM dz)
Huntington disease
bilateral caudate & putamen atrophy w frontal horn enlargement
Causes of bilateral BG/thalamic hypodensity or signal abnormality
?needs work
- Hypoxic ischemic injury (also cortical GM)
- CO (GP)
- MeOH (putamen)
- viral encephalitis
- Wilson’s dz
- mitochondrial d/o (e.g. Leigh)
- C-J dz
Bithalamic:
- venous infarct
- CVA: artery of percheron
- West Nile
- Wernicke’s
Causes of communicating hydrocephalus
NPH
SAH or IVH
Meningitis
Post-inflammatory scarring of arachnoid granulations
Normal marrow:disc brightness on MR
T1: marrow > disc. Reverse suggests diffuse infiltration (e.g. leukemia).
T2: disc > marrow. Reverse suggests disc dessication.
Causes of non-communicating hydrocephalus
Intraventricular tumor
Focal mass effect
Orbital pathology
Muscles:
Graves ophthalmopathy
Pseudotumor cerebri (painful)
Lymphoma
Nerve:
Optic neuritis
Meningioma (peripheral enh)
Glioma (NF-1)
Ddx U-fiber lesions
PML Radiation injury PRES MS (e.g. Marburg) ADEM Viral encephalitis
Others??
Evaluation of temporal bones
.
Ddx long segment cord abnL
Transverse myelitis as a result of any of the following: Idiopathic ADEM Sarcoid CVD (Sjogren, Rheumatoid dz, Lupus) MS Vasculitis
Others not to miss:
XRT (look at verts for fatty prolif in portal)
Cord infarct
dAVF w cord changes
Ddx sacral mass
Chordoma (T2 bright areas also mildly enh, soap bubble "physaliferous" cells) Chondrosarcoma Plasmacytoma/MM Met Lymphoma Osteosarcoma Osteochondromatosis (rarely)
GCT
Brown tumor
Others?
Making a CTA perfusion map
- Open Brilliance
- Select Perfusion Series, always with 240 images. If displayed in PACS, can choose “Open Selected Series”
- Check curves, adjust by clicking back arrow to step 1 if needed:
- Adjust windows 1st in order to better identify vessels
- Can clear prior curves by clicking “Ax” icon bottom right
- Both must start near zero
- Select ACA for artery
- Select Superior Sag Sinus or Straight Sinus for vein (start ROI within parenchyma away from bone in order to have an accurate selection).
- Arterial peak should be earlier and lower
- Venous peak should be later and much taller - Review perfusion maps, then review superimposed maps by selecting left hemisphere and right hemisphere icons individually (red core, green infarct)
- Send to PACS via drop-down menu next to floppy disk icon, select “Save Batch As”, name w your initials, click Ok, might take a few mins to show up.
-use vitrea 3D to ID vessel occlusions
- MTT/TTP most sens, least sp… look here first for subtle abnL, ten see if real on CBV/CBF (CBF most spec)
- decreased CBV = DWI correlate = infarct
- Mismatch btw CBV and CBF = penimbra
- If no change in CBV, but decreased CBF then hypoperfused but no infarct. Dont just go by automated red/green areas!
- normal CBF roi (50-100), penumbra cbf (15-30), infarct < 15
Core infarct vs. Penumbra
- CBV: decreased in core infarct, normal/slightly high in penumbra
- Both have increased MTT and decreased CBF
** if no CBV abnL, then all hypoperf w/o infarct!
Recurrent tumor vs. rad necrosis
Recurrence will be hot on PET
Ddx solitary focal cortical lesion
-Cortical dysplasia
-DNET (no/min enh)
-Neoplasm (oligo Ca, low-grade astro, paraganglioma, ganglioglioma +/- enh, others)
?
Lepto v. Pachymeninges
Lepto= pia + arachnoid Pachy= dura
Carotid-cav fistula
Dx:
Contrast in sinus on CTA
Signal in sinus on MRA-TOF
Types:
Direct (ICA)
Indirect (ECA collat)
Us p-traumatic, others?
Complications blindness from pressure on ON
Tumefactive MS?
Marburg
Balo concentric sclerosis
Types of heterotopia?
Band
Subependymal
Focal subcortical
Intraventricular fat
Ruptured epidermoid if antidependent T1
Others?
Ddx Gd-enhancing nerves (incl CN)
Leptomeningeal mets Lymphoma Sarcoid Viral neuritis Demyelinating dz (Lyme, MS, Guillam-Barre, CIDP, etc) Others?
How to ID dominant hemisphere
Marginal ramus of Sulvian fissure is more horiz (v. ascending on non-dom side)
ICA segments
C1- cervical
INTRACRANIAL:
Pre-cav:
C2- petrous (vert, horiz)
C3- lacerum
Cavernous:
C4- cav
(ant genu)
C5- clinoid
Supra-clinoid:
C6- ophto = 1st intradural!
Terminal:
C7- terminal
MCA segments
M1- horiz
M2- insular
M3- opercular
M4- cortical branches
ACA segments
A1- horiz/pre-comm
A2- vertical/post-comm
A3- distal/pericallosal
PCA segments
P1- mesen/pre-comm
P2- ambient
P3- quadrigeminal
P4- calcarine
Vert segments
V1- extraosseous V2- foraminal (C6-C3) V3- extraspinal (enters dura @ foramen magnum) V4- intradural/intracranial
40% codominant
40% L
20% R
All BG supplied by ___ lenticulostriates EXCEPT ___
-MCA (M1)
-caudate head supplied by ACA lenticulastriate branch called
recurrent artery of Huebner
Blood supply of thalamus
- multiple thalamoperforators from PCA & basilar tip
- Artery of Percheron = anatomic variant w single large perforator from P1 supplying bilat thalami & median midbrain
Broca’s area
posterior aspect of inferior frontal gyrus, in pars operc?
Wernicke’s area
posterior aspect of superior temporal gyrus, more spec?
Venous drainage of brain:
- Galen tributaries & path to jugular
- anastamotic cortical veins
- Vein of Galen (convergence of bilat ICVs, bilt basal veins of Rosenthal)
- Galen + ISS join @ straight sinus
- Straight + SSS + bilat transverse sinuses join at torcular heterophil
- transverse to sigmoid to jugular
Anastamotic cortical veins
- vein of Trolard joins SSS
- vein of Labbe joins transverse
- superficial MCV joins @ jcn of Trolard/Labbe
Cavernous sinus
- drainage
- CN
Inf and sup petrosal?
Blood supply of posterior limb of internal capsule
Anterior choroidal artery from ?ICA, just prox to circle of Willis
ECA to ICA collaterals
- Internal maxillary artery, ?mult others in skull base
- Superficial temporal to ophthalmic
- others?
Ddx parotid mass
- Benign Mixed Tumor (aka pleomorphic adenoma)
- Warthin tumor
- Met (Necrotic w SCCA)
Others: Salivary tumors NHL Schwannoma 1st BC cyst
Septo-optic dysplasia
1- Absent septum pellucidum
2- Hypoplastic ON (T2 bright rim of CSF on coronal)
3- small pituitary
Ddx dural thickening and enhancement
- En plaque meningioma
- Mets (esp prostate)
- Lymphoma
- Post-op
Sarcoid
TB
Intracranial HoTN (diffuse)
Pseudotumor
Causes of mastoid effusion
- Eustachian tube dysfcn (intubated)
- Blood from T-bone fxr
- Mastoiditis
- NP mass
Post-angio staining on CT
.
Ddx mandible lesion
?
Osteonecrosis
Osteosarcoma
Fibrous dysplasia
Ddx petrous apex mass
Chondrosarcoma
Signal chars
-
Ddx bilat BG calcs
Aging
Farrs dz
Metabolic (any PTH dz) TORCHES HIV (= AIDS if in infant) Cystercercosis Chronic CO poisoning
Arterial supply of precuneus (occipital lobe)
MCA! Not PCA
Location of PCA thrombus if thalami spared
P3 or P4
If thalami involved, must be at P1/P2
Ddx pulsatile tinnitus
Glomus tymp Dehisc jug ?ICA ?others Glomus jug?
Ddx calcific longus colli
Calcific tendinitis of longus colli
Focal ca w prevertebral ST swelling
Neck pain, mild fever, odynophagia, no white count
Approach to FLAIR abnL
volume neg
vol neutral
volume positive
Ddx sulcal FLAIR abnL
Meningitis
SAH
High flow 100% O2
Venous congestion
Culprit aneurysm
Focal hemorrhage
Largest
Irreg
(in that order)
Ddx medial temporal lobe FLAIR
HSV
Other viral: EEE?
Status epilepticus
Limbic encephalitis
Ddx widespread white matter FLAIR hyperintensity
- Delayed post-hypoxic leukoencephalopathy (luid interval)
- Heroine inhalation
- PRES
- PML
- HIV encephalopathy
- Dysmyelination d/o (Metachromatic Leukodystrophy)
- usual nonspec wm stuff…?
Ddx thickened calvarium
fibrous dysplasia (w 2o ABC) Paget's hemangioma anemias Dilantin acromegaly hyperostosis
