CTC Neuro Flashcards
(192 cards)
1
Q
Pattern of myelination in the brain.
A
Inferior to superior
Posterior to anterior
Central to peripheral
Sensory then motor.
Subcortical last.
At birth, the brainstem and posterior limb of internal capsule are myelinated.
Immature brain is opposite T1 and T2.
The anterior and posterior pituitary are bright at birth.
2
Q
How does the corpus callosum develop?
A
Front to back, then rostrum.
3
Q
Order of development of the sinuses?
A
Maxillary, Ethmoid, Sphenoid, and frontal last.
4
Q
Contents of foramen ovale
A
V3 and accessory meningeal artery
5
Q
Contents of inferior orbital fissure
A
V2
6
Q
What does NOT run through the cavernous sinus?
A
CN2
V3
7
Q
What are the branches of the external carotid artery?
A
Some Administrators Like Fucking Over Poor Medical Students
Superior Thyroid Ascending Pharyngeal Lingual Facial Occipital Posterior Auricular Maxillary Superficial Temporal
8
Q
Segments of the ICA
A
Cervical Petrous Lacerum - adjacent to Meckels cave Cavernous - HTN aneurysm Clinoid Opthalmic - Aneurysm formation Communicating - CN III palsy
9
Q
Location of CN3 in COW?
A
Between PCA and SCA
10
Q
Where does the Anaterior Choroidal Artery arise?
A
MCA
11
Q
What are the superficial and deep cerebral veins?
A
Superficial: Superficial cerebral veins Superior anastomic vein of Trolard Inferior anastomotic vein of Labbe Superficial middle cerebral veins
Deep:
Basal Vein of Rosenthal
Vein of Galen
Inferior Petrosal Sinus
12
Q
What is the relationship of the Veins of Labbe and Trolard?
A
Share drainage of the same territory - one gets bigger, the other gets smaller.
Vein of Labbe: Large draining vein, connecting the superficial middle vein and the transverse sinus
Vein of Trolard: Smaller (usually) vein, connecting the superficial middle vein and sagittal sinus.
Basal Vein of Rosenthal: Deep vein that passes lateral to the midbrain through the ambient cistern and drains into the vein of Galen. Courses similar to the PCA.
Vein of Galen: Big vein formed by the union of two internal cerebral veins.
13
Q
What to think of with CN3 and CN6 palsies?
A
CN3: PComm Aneurysm
CN6: Increased ICP.
14
Q
Cause of non-obstructive hydrocephalus?
A
Something that produces CSF - Choroid plexus papilloma.
15
Q
What is Hurst Disease?
A
Acute Hemorrhagic Leukoencephalitis - fulminant form of ADEM with massive brain swelling and death. Hemorrhagic part is only seen on autopsy.
16
Q
What is PRES?
A
Posterior Reversible Encephalopathy Syndrome
HTN or chemotherapy.
Asymmetric cortical and subcortical white matter edema (usually in parietal occipital regions). Does NOT diffusion restrict.
17
Q
What does Osmotic Demyelination Syndrome look like?
A
T2 bright in the central pons (spares the periphery).
Can also have extra-pontine presentation involving the basal ganglia, external capsule, amygdala, and cerebellum.
18
Q
What does Wernicke Encephalopathy look like?
A
Thiamine deficiency.
Enhancement of the mammillary bodies.
Also T2/FLAIR signal in the bilateral medial thalamus and periaqueductal gray.
19
Q
What does Carbon Monoxide Poisoning Look like?
A
CT hypodensity/T2 bright GLOBUS PALLIDUS
Carbon monoxide causes “globus” warming.
20
Q
What is Marchiafava-Bignami?
A
Swelling and T2 bright signal affecting the corpus callosum - typically beginning in the body, then genu, and lastly splenium).
Will involve the central fibers and spare the dorsal and ventral fibers (“sandwich sign” on sagittal imaging).
21
Q
What does Methanol Poisoning look like?
A
Optic nerve atrophy
Hemorrhagic PUTAMEN and subcortical white matter necrosis.
22
Q
What is Disseminated Necrotizing Leukoencephalopathy?
A
Severe WM changes which demonstrate ring enhancement - classically with leukemia patients undergoing radiation and chemotherapy - can be fatal.
Can get T2 effects acutely in white mater that can progress to atrophy with chemotherapy. Enhancement or mass effect is rare unless its very severe. Children receiving both radiation and chemotherapy can sometimes develop calcifications.
23
Q
Findings of Alzheimers
A
Hippocampal atrophy (first) out of proportion to the rest of the brain atrophy. Temporal horn atrophy >3 mm.
24
Q
Findings in Lewy Body Dementia
A
Similar clinical picture to Dementia with Parkinsons, but dementia comes first.
Hippocampi remain normal in size and you have some decreased FDG uptake in the lateral occipital cortex with sparing of the mid posterior cingulate gyrus (Cingulate Island Sign).
25
What is Binswanger Disease?
Subcortical leukcoencephalopahy that affects older people (55 and up), strongly associated with HTN.
Form of small vessel vascular dementia. Spares the subcortical U fibers.
26
PET findings in Alzheimer, Multi-infarct, Dementia with Lewy Bodies, Picks/Frontotemporal/Depression and Huntingtons
Alzheimers - Low posterior temporoparietal cortical activity - Identical to Parkinson Dementia
Multi-Infarct - Scattered areas of decreased activity - Lyme, HIV, and Vasculitis are mimics
Dementia with Lewy Bodies - Low in lateral occipital cortex - Preservation of the mid posterior cingulate gyrus (Cingulate Island Sign)
Picks/Frontotemporal/Depression - Low Frontal Lobe - Depression is a mimic
Huntingtons - Low activity in caudate nucleus and putamen.
27
MC TORCH infection?
CMV - Toxo is 2nd MC.
Likes the germinal matrix and causes periventricular tissue necrosis. Periventricular calcifications.
CMV has the highest association with polymicrogyria.
28
What is Toxoplasmosis?
2nd MC TORCH - CMV is MC. Cat shit.
Calcification pattern is more random and affects the basal ganglia. Frequency increased in the third trimester (but only a problem in the first two).
Hydrocephalus.
29
What is CNS Rubella?
Calcs are less common than in other TORCH infections.
MRI: Focal high T2 signal might be seen in white matter (related to vasculopathy and ischemic injury).
30
Peds HSV CNS infection?
HSV-2
Unlike adults, does not primarily affect the limbic system, but instead affects the endothelial cells resulting in thrombus and hemorrhagic infarction with resulting encephalomalacia and atrophy.
31
What is peds HIV CNS infection?
Not a TORCH, but does occur during pregnancy, at delivery, or through breast feeding.
Brain atrophy predominantly in the frontal lobes.
May have faint BG enhancement seen on CT and MRI preceding the appearance of BG calcification.
32
CNS TORCH infections
```
CMV = MC, periventricular calcs, polymicrogyria
Toxo = Hydro, BG calcs.
Rubella = Vasculopathy/Ischemia. High T2 signal - less calcs
HSV = Hemorrhagic Infarct and lead to bad encephalomalacia (hydranencephaly)
HIV = Brain atrophy in frontal lobes.
```
33
MC opportunistic infection in AIDS
Toxo - T1 dark and T2 bright, ring enhancing lesions - NOT diffusion restricting. Thallium cold.
MC fungal infection is Cryptococcus
34
HIV Encephalitis vs PML?
HIV: CD4 <200. Symmetric increased T2/FLAIR signal in the deep white matter. T1 will be normal. Lesions will not enhance. May be associated brain atrophy. Spares the subcortical U-fibers.
PML: JC virus. CD4<50. Single or multiple scattered hypodensities, with corresponding T1 hypointensity. T2/FLAIR hyperintensities out of proportion to mass effect. Involve the subcortical U-fibers. Asymmetry helps differentiate from HIV encephalitis.
35
MRI findings of AIDS encephalitis, PML, CMV, Toxo, and Cryptococcus
AIDS Encephalitis: Symmetric T2 bright
PML: Asymmetric T2 bright, T1 dark
CMV: Periventricular T2 bright, Ependymal enhancement
Toxo: Ring enhancement, Thallium cold
Cryptococcus: Dilated perivascular spaces, basilar meningitis.
36
Difference between TB meningitis and sarcoid
Enhancement of the basilar meninges with minimal nodularity. Can have dystrophic calcs.
Can have hydrocephalus with TB.
37
What is Limbic Encephalitis?
Paraneoplastic syndrome - usually small cell lung cancer. Not an infection.
Looks similar to HSV (titer will be negative). Do lung cancer screening.
38
What does West Nile look like?
T2 bright basal ganglia and thalamus with corresponding restricted diffusion. Hemorrhage is sometimes seen.
39
Findings of CJD?
DWI showing cortical gyriform restricted signal - most sensitive sign.
Hockey stick sign/Pulvinar Sign - restricted diffusion in the dorsal medial thalamus (which looks like a hockey stick).
Series of MRs or CTs showing rapidly progressive atrophy.
40
What is Neurocysticercosis?
Undercooked pork. Tinea Solium. Involvement of the subarachnoid space over the cerebral hemispheres, basal cisterns, brain parenchyma, and ventricles. Involvement of the basal cisterns carries the worst outcome.
4 Stages:
Vesicular - Thin walled cyst (iso-iso T1/T2 + no edema)
Colloidal - Hyperdense Cyst (bright-bright T1/T2 + edema)
Granular - cyst shrinks, wall thickens (less edema)
Nodular - small calcified lesion (no edema)
41
Peds Supratentorial vs Infratentorial Tumors
Supratentorial
Astrocytoma (including GBM), PXA, PNET, DNET
Infratentorial
JPA, Medulloblastoma, Ependymoma, Ependymoma, Braainstem Astrocytoma
42
Adults Supratentorial vs Infratentorial Tumors
Supratentorial
Mets ++
Astrocytoma (including GBM)
Oligodendroglioma
Infratentorial
JPA
Hemangioblastoma
43
Skull base tumors
```
Chordoma (midline)
Chondrosarcoma (off midline)
Esthesioneuroblastoma
Sinonasal Carcinoma
Mets
Lymphoma
Paraganglioma
```
44
Sella/Parasellar Tumors
```
Sarcoid
Aneurysm
Adenoma
Rathke's Cyst
Teratoma
Craniopharyngioma
Hamartoma
Hypothalamic Glioma
Meningioma
Optic Nerve Glioma
```
45
Intraventricular Tumors
```
Ependymoma
Subependymoma
Choroid Plexus Papilloma
Central Neurocytoma
Colloid Cyst
Meningioma
Giant Cell Astrocytoma
```
46
CP Angle Tumors
Schwannoma
Meningioma
Epidermoid
Arachnoid Cyst
47
Pineal Region Tumors
```
Pineocytoma
Pineoblastoma
PNET
Tectal Glioma
Meningioma
Dermoid
Germinoma
```
48
What are the "cortically based" tumors?
Most intra-axial tumors are located in the white matter.
Cortically based (DOG):
Dysembryoplastic Neuroepithelial Tumors (DNET)
Oligodendroglioma
Ganglioglioma
49
Tumor syndromes
NF1: Optic gliomas and astrocytomas
NF2: MSME: Multiple schwannomas, meningiomas, ependymomas
TS: Subependymal tubers, IV giant cell astrocytomas
VHL: Hemangioblastomas
50
What are the low grade intraxial tumors that enhance?
Ganglioglioma and juvenile pilocytic astrocytoma
Extraxial tumors will enhance and tumors that are high grade enough to disrupt the BBB.
51
Hemorrhagic mets
MR and CT
Melanoma
Renal
Carcinoid/Choriocarcinoma
Thyroid
52
What is Turncot Syndrome?
GI polyps and Medulloblastoma and GBMs.
53
What is associated with an Oligodendroglioma?
1p/19q deletion - has a better outcome.
Calcifies 90% of the time. MC in frontal lobe and "expands the cortex" - cortical infiltration and marked thickening.
54
Hormones in the anterior and posterior pitutitary
FLAT-PEG
Anterior:
FSH, LSH, ADH, TSH
Posterior:
Prolactin, Endorphins, GSH
55
What drug can result in Pituitary Apoplexy?
Bromocriptine (or other prolactin drugs)
56
What is a Craniopharyngioma?
Two types: Papillary (adults) and Adamantinomatous.
Papillary type in adults are solid and do not have calcifications. Recur less frequently than tha Adamantinomatous form (b/c they are encapsulated). Strongly enhance.
Adamantinomatous - calcified. Recur. "Machinery oil"
57
What is a Hemangiopericytoma?
Soft tissue sarcoma that can mimic an aggressive meningioma b/c they both enhance homogeneously. Can mimic a dural tail, with a narrow base of dural attachment.
Won't calcify or cause hyperostosis, but will invade the skull.
58
What is a Desmoplastic Infantile Ganglioglioma/Astrocytoma "DIG"?
Large cystic tumors that like to involve the superficial cerebral cortex and leptomeninges. Have a better prognosis than Atypical Teratoma/Rhabdoid tumors.
Always arise in the supratentorial location usually involving more than one lobe (frontal and parietal MC), and usually present before first birthday.
Buzzword is "rapidly increasing head circumference".
59
Brain mets in a kid
Neuroblastoma - like the bones and the dura.
Characteristically involves the posterolateral part of the orbit where the frontal bone and greater wing of the sphenoid meet (EG can do this too).
60
What is a Juvenile Pilocytic Astrocytoma?
Cyst with a nodule in a kid - nodule will enhance. Posterior fossa (or optic chiasm).
61
What is a DNET?
Dysembryoplastic Neuroepithelial Tumors
Kid with drug resistant seizures. Temporal lobe. Focal cortical dysplasia is seen in 80%.
Hypodense on CT and MRI will be little if any surrounding edema. High T2 signal "bubbly lesion."
62
What is a PXA?
Pleomorphic Xanthroastrocytoma
Superficial tumor ALWAYS supratentorial and usually involves the temporal lobe.
Cyst with a nodule. Usually no peritumoral T2 signal. Frequently invades the leptomeninges. Look like a Desmoplastic Infantile Glioma but not in an infant.
63
What is a PNET?
Primitive Neuroectodermal Tumor
Same histo as a medulloblastoma. Supratentorial (deep white matter). Classically very heterogeneous and known for metting outside the CNS.
64
What is Garlin Syndrome?
Medulloblastoma, look for thick dural calcs.
Get basal cell skin cancer after radiation and have odontogenic cysts.
65
What are the 3 tumors associated with the Pineal Gland?
Germinoma- most common.
Pineocytoma
Pineoblastoma
66
What is a Pineal Germinoma?
MC pineal tumor. Boys.
Precocious puberty may occur from secretion of hCG. Mass containing fat and calcifications with variable contrast enhancement. Heterogeneous on T1 and T2 (b/c of mixed components)
"Engulfed" calcifications
67
What is a Pineocytoma?
Rare in childhood. Well-circumscribed, and non-invasive. Tend to be more solid, and the solid component do typically enhance.
"Exploded" calcifications
68
What is a Pineoblastoma?
Does occur in childhood. Unlike pineocytoma high invasive - like a PNET of the pineal gland.
Associated with retinoblastomas. Heterogeneous and enhance avidly.
"Exploded" calcifications
69
Brain tumor syndromes
NF-1: Optic nerve gliomas
NF-2: MSME: Multiple schwanomas, meningiomas, and ependymomas
VHL: Hemangioblastoma (brain and spine)
TS: Subependymal Giant Cell Astrocytoma, Cortical tubers
Nevoid Basal Cell Syndrome (Gorlin): Medulloblastoma
Turcot: GBM, Medulloblastoma
Cowdens: Lhermitte-Dulcos (Dysplastic cerebellar gangliocytoma).
70
Things associated with LeFort 1, 2, and 3
LeFort 1: Lateral Nasal Aperture
LeFort 2: Inferior Orbital Rim and Orbital Floor
LeFort 3: Zygomatic Arch and Lateral Orbital Rim/Wall
71
Watershed infarcts in a kid
Moyamoya
72
What is "Fogging" with strokes?
Phase in the evolution of stroke when the infarcted brain looks like normal tissue. Seen around 2-3 weeks post infarct. Usually noncon CT, but T2 can have similar effect. Can see infarct with IV contrast.
73
Things that restrict diffusion other than stroke?
```
Bacterial Abscess
CJD (cortical)
Herpes
Epidermoids
Hypercellular brain tumors (classic is lymphoma)
Acute MS lesions
Oxyhemoglobin
Post Ictal States
```
74
What is Venous Infarct?
Higher risk for hemorrhagic transformation.
Dehydration in babies. Adults- coagulopathies (protein C and S) and OCPs. MC site is the sagittal sinus.
Tend to have heterogeneous restricted diffusion. Can result in vasogenic edema that eventually progresses to stroke and cytotoxic edema.
Arterial stroke = cytotoxic edema
Venous stroke = vasogenic edema + cytotoxic edema.
75
What are the stigmata of chronic venous thrombosis?
Development of dural AVF, or increased CSF pressure from impaired drainage.
76
What are the subtypes of aneurysms?
Fusiform- Associated with PAN, connective tissue disorders, or syphilis. MC affect the posterior circulation. May mimic a CPA mass.
Pedicle Aneurysm - associated with AVM. Found on the artery feeding the AVM. May be higher risk to bleed than the AVM itself (b/c of high flow)
Blister Aneurysm - Broad-based at a non-branch point (supraclinoid ICA is MC). Angio is often negative.
Infundibular Widening - Not a true aneurysm, but a funnel-shaped enlargement at the origin of the PComm at the junction with the ICA. "Not greater than 3mm."
77
Increased bleeding risks with high flow AVMs
Small size of AVM (higher pressure), single draining vein, intranidal/perinidal aneurysm, basal ganglia/thalamic/periventricular location.
78
Non-SAH causes of vasospasm?
Meningitis, PRES, and Migraines
79
Types of CNS vasculitis
Primary CNS vasculitis: Primary Angiitis of the CNS
Secondary CNS vasculitis from infection or sarcoid: Meningitis (bacterial, TB, Fungal), septic embolus, sarcoid
Systemic vasculitis with CNS involvement: PAN, Temporal arteritis, Wegeners, Takaysu's
CNS vasculitis from a systemic disease: Cocaine use, RA, SLE, Lyme's
80
What are the MC systemic vasculitis and collagen vascular disease to involve the CNS
PAN is MC systemic vasculitis
| SLE is MC CVD.
81
Things to know about Moyamoya
Buzword - "Puff of Smoke" - for angiographic appearance.
Watershed distribution
In a child think sickle cell
Other notable associations: NF, prior radiation, Downs
Bi-modal age distribution (early childhood and middle age)
Children stroke, acute bleeds
82
What is CADASIL?
Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy
40 y/o presenting with migraine HA then eventually dementia.
MRI: severe WM disease involving multiple vascular territories in the frontal and temporal lobe. Occipital lobes are often spared.
83
Differences between Lobar, Semi-lobar, and Alobar Holoprosencephaly?
Lobar (mild) - R and L hemispheres are separate (ant/inf frontal still sometimes fused). May be limited to absent septum pellucidum. Pituiary problems are common.
Semi-lobar - Basic structure present but fused at the thalami. Posterior brain is normal. Olfactory tracts and bulbs are gone.
Alobar (severe)- Single large ventricle with fusion of the thalami and BG. No falx. No corpus callosum.
84
What are the Holoprosencephaly associations?
Single Midline Monster Eye
Solitary Median Maxillary Incisor (MEGA-Incisor)
Nasal Process Overgrowth leading to Pyriform Aperture Stenosis
85
What is Meckel-Gruber Syndrome?
Holoprosencephaly
Multiple Renal Cysts
Polydactyly
86
What is Hemimegalencephaly?
Enlargement of all or parts of one cerebral hemisphere. Problem of neuronal differentiation and cell migration in a single hemisphere. Affected hemisphere may have focal or diffuse neuronal migration defects including areas of polymicrogyria, pachygyria, and heterotopia.
Trick: look at which side (the big side or little side) has the ventriculomegaly.
Small Side + Big ventricle = atropy (as might be seen with Rasmussen's Encephalitis)
Big side + Big ventricle + Hemimegalencephaly
87
What is Lissencephaly-Pachygyria Spectrum?
Cause relative smoothness of the brain surface. Agyria (no gyri), pachygyria (broad gyri), and lissencephaly (smooth brain surface).
Type I/Classic = smooth brain. Arrest of migration. "Figure 8", "hour glass appearance", "vertically oriented shallow Sylvian fissures". Associated with band heterotopias.
Type II = Cobblestone brain. Over migration. Not a band of heterotopia and the cortex is thinner than type I.
88
Difference between subepencymal hetertopias with subependymal tubers of TS?
Tubers are usually higher on T2 than gray matter and often calcified (except in early childhood).
89
Associations with Schizencephaly?
Optic Nerve Hypoplasia
Absent Septum Pellucidum
Epilepsy
90
Difference between Open Lip Schizencephaly and Porencephalic Cyst
Schizencephalic cleft should be lined with gray matter and is a true malformation.
Porencephlic cyst is just a hole from a prior encephaloclastic event (ischemia). Normal forming but massive insult makes you look like you didn't form.
91
Association with Chiari I malformation?
Klippel-Feil Syndrome (congenital C-spine fusion)
92
Findings with Chiari II malformation?
Myelomeningocele - Lumbar Spine
Towering cerebellum
Tectal plate beaking
Long skinny 4th ventricle (elongated craniocaudally, short in other dimensions) - a normal 4th ventricle may suggest shunt malfunction
Interdigitated cerebral gyri (most likely shown on axial CT, single image)
93
What is the MC craniosynostosis?
Scaphocephaly (sagittal suture) - Often referred to dolichocephaly.
94
What is Brachycephaly and what is it associated with?
Coronal and/or Lambdoid suture
Aperts: Brachycephaly + Fused fingers
Crouzons: Usually Brachycephaly (but not always) + first arch (maxilla and mandible hypoplasia)
Cleidocranial Dysostosis: Brachycephaly + Wormian Bones + Absent Clavicles
95
What is Aperts Syndrome?
Brachycephaly + Fused fingers
96
What is Crouzons Syndrome?
Usually Brachycephaly (but not always) + first arch (maxilla and mandible hypoplasia)
97
What is Cleidocranial Dysostosis?
Brachycephaly + Wormian Bones + Absent Clavicles
98
What is Plagiocephaly?
Unilateral coronal or lambdoid suture fusion (frontal or occipital plagiocephaly).
Ipsilateral coronal fusion can elevate the superior orbital wall and cause a harlequin eye.
99
What is the Metropic Suture and what does it's fusion cause?
Down frontal bone.
Trigonocephaly - pointy forehead.
100
Trivia for Craniosynostosis
MC type = Sagittal (dolichocephaly or scaphocephaly)
Sagittal suture is most always (80%) affects boys
Coronal suture craniosynostosis affects more girls
"Harlequin eye" = unilateral coronal suture craniosynostosis (lifts supra-orbital margin)
Lambdoid Craniosynostosis favors the right side (70%)
Turricephaly (the tower) is from both coronal and lambdoid fusion.
101
Associations with choanal atresia?
```
CHARGE
Crouzons
DiGeorge
Treacher Colins
Fetal Alcohol Syndrome
```
102
What is associated with Piriform Aperture Stenosis?
Hypothalamic-Pituitary-Adrenal Axis Dysfunction
Can occur in isolation or with choanal atresia.
103
What is MELAS?
Mitochondrial disorder with lactic acidosis and stroke like symptoms.
Increased lactate, decreased NAA.
104
Tricks for Canavans, Alexanders, and Metachromatic Leukodystrophies?
Canavans - SPECT - elevated NAA
Alexanders - big head (Alexander the great), has frontal white matter involvement (personality disorder)
Metachromatic - MC - "tigroid". Dark spots or stripes w/in the T2 bright demyelinated periventricular white matter disease.
105
What is Metachromatic Leukodystrophy?
Normal Head Size.
Infantile form 1-2 y/o. Juvenile form 5-7
Diffuse white matter involvement, with tigroid appearance.
MC Leukocystrophy. Deficiency of the enzyme arylsufatase A
106
What is Adreno Leukodystrophy?
Normal head
5-10 years old
Symmetric occipital and splenium of the corpus callosum white matter involvement
Sex-linked recessive condition (peroxisomal enzyme deficiency) occurring only in boys.
107
What is Leigh Disease?
Normal Head
Less than 5 y/o.
Focal areas of subcortical white matter. BG and periaqueductal gray matter involvement.
Also called subacute necrotizing encephalomyelopathy. Mitochondrial enzyme defect.
108
What is Alexander Disease?
Big Head.
Less than 1 y/o
Frontal WM involvement
109
What is Canavan Disease?
Big Head
Less than 1 y/o
Diffuse bilateral subcortical U fibers
Elevated NAA (MRS)
110
What is the highest peak with SPECT?
NAA
Usually super high with Canavans
111
In what processes in Choline elevated in SPECT?
Anything that causes cell turnover (tumor, infarct, or inflammation)
112
When is it normal to see elevated lactate on SPECT?
First few hours of life.
113
When is Myoinositol elevated on SPECT?
Alzheimers and low grade gliomas
114
Finding of meningiomas on SPECT?
Do NOT have elevated NAA
115
What is elevated on SPECT with hepatic encephalopathy?
Glutamine
116
Findings of High Grade Tumor on SPECT?
Choline Up, NAA down; Lactate and Lipids up
117
Findings of Low Grade Tumor on SPECT?
Choline Down, NAA down, Inositol Up.
118
Pattern of Radiation Necrosis on SPECT?
Choline Down, NAA Down, and Lactate Up.
119
Cephalocele involving the Petrous Apex?
Cystic expansion and herniation of the posterolateral portion of Meckel's cave into the superomedial aspect of the petrous apex.
120
What are the 2 main variants of ICA anatomy?
Persistent stapedial artery
Aberrant ICA.
Can give pulsatile tinnitus - don't biopsy.
121
MC primary petrous apex lesion
Cholesterol granuloma - T1 and T2 bright - NO diffusion restriction.
122
What is Grandenigo Syndrome?
Complication of apical petrositis when Dorello's Canal (CN6) is involved.
Triad: Otomastoiditis, facial pain (trigeminal neuropathy) and lateral rectus palsy.
123
What is an Endolymphatic Sac Tumor?
Rare tumor of the endolymphatic sac and duct. Can grow into the CPA.
Internal amorphous calcifications on CT. T2 bright with intense inhancement. Very vascular with flow voids and tumor blush on angio.
VHL.
124
What is Large Vestibular Aqueduct Syndrome?
Vestibular aqueduct is a bony canal that connects the vestibule (inner ear) with the endolymphatic sac. Becomes enlarged (>1.5 mm) it is associated with progressive sensorineural hearing loss.
Associated with absence of the bony modiolus (conical shaped central axis in the cochlea) in more than 90% of patients.
125
Types of Otosclerosis?
Fenestral - bony resorption anterior to the oval window at the fissula ante fenestram - footplate will fuse to the oval window.
Retro-fenestral - More severe when has progressed to have demineralization around the cochlea - Usually has a sensorineural component and is bilateral and symmetric nearly 100% of the time.
126
What is Otitic Hydrocephalus?
Venous thrombosis of the DVS can affect resorption of CSF and leads to hydrocephalus.
127
Order of destruction of Cholesteatoma?
Scutum
Ossicles (long process of incus)
Lateral segment of the semi-circular canal
128
Differences between Pars Flaccida and Pars Tensa Type Cholesteatomas?
Pars Flaccida:
Acquired more common- grow into Prussak's space.
Scutum is eroeded early
Malleus head is displaced medially
Long process of the incus is the MC segment of the ossiscular chain to be eroded.
Fistula to the semi-circular canal MC involves the lateral segment.
Pars Tensa:
Inner ear structures are involved earlier and more often
Less common than flaccida type.
129
What is a Labrynthine Fistula?
Potential complication of cholesteatoma (can also be congenital or iatrogenic) - bony defect b/t the inner ear and tympanic cavity.
Lateral semicircular canal is most often involved.
130
What causes "noise induced vertigo"?
Superior semicircular canal dehiscence.
Longstanding ICP.
131
What parts of the facial nerve do NOT normally enhance?
Cisternal, canalicular and labyrinthine
Remainder - intratemporal course can enhance (tympanic, mastoid). Perineural venous plexus.
132
What causes abnormal enhancement of the facial nerve?
Bells Palsy
Lymes
Ramsay Hunt
Cancer
133
When do you damage the facial nerve?
Transverse T-bone fractures - more than longitudinal.
134
What is an Antrochoanal Polyp?
```
Young adults (30-40s)
Nasal congestion/obstructive symptoms.
Arise w/in the maxillary sinus and passes through and enlarges the sinus ostium (or accessory ostium)
```
"Widening of the maxillary ostium." - No bony destruction but smooth enlargement of the sinus.
Polyp will extend into the nasopharynx.
Big inflammatory polyp with a thin stalk arising from the maxillary sinus.
135
What is an Inverting Papilloma?
Classic location - lateral wall of nasal cavity - most frequently related to the middle turbinate. Impaired maxillary drainage.
Focal hyperostosis tends to occur at the tumor origin.
MRI buzzword "cerebriform pattern" - look like brain on T1 and T2.
10% harbor a SCC.
136
NM study for enthesioneuroblastoma?
Octreotide scan
137
What is a SNUC?
Undifferentiated SCC - bigger version.
Ethmoid origin more common than maxillary.
Large, typically >4 cm on presentation.
Fungating and poorly defined heterogeneous enhancement with necrosis.
138
What is the main arterial supply of the posterior nose?
Sphenopalatine artery - terminal branch of the internal maxillary artery.
Can have a variant anastomosis between the ECA and ophthalmic artery - don't want to embolize the eye.
139
"Sack of marbles" - fluid sack with globules of fat in the floor of the mouth, midline?
Floor of mouth Dermoid/Epidermoid
140
What is Torus Planus?
Normal variant - Bony exostosis that comes off the hard palate in the midline.
Grandma's dentures won't stay in.
141
MC salivary gland to get sialolithiasis?
Submandibular gland duct (Warton's)
142
What dictates spread of infection to the sublingual and submandibular spaces?
Attachment of the mylohyoid muscle to the mylohyoid ridge.
Above the line (anterior mandibular teeth) goes to the sublingual space and below (2nd and 3rd molars) to the submandibular space.
143
Cause of osteonecrosis of the mandible?
Bisphosphonate Treatment.
Also with radiation and radium.
144
MC major and minor salivary gland tumor?
Pleomorphic adenoma (benign mixed tumor). MC in the parotid.
T2 bright with rim of low signal. Have a small malignant potential.
145
What is a Warthins Tumor?
2nd MC benign tumor. Only in the parotid gland.
Usually cystic, in a male, bilateral (15%), and in a smoker.
Takes up pertechnetate also parotid oncocytoma.
146
What parotid tumors take up pertechnetate?
Warthins
| Parotid Oncocytoma.
147
MC malignant tumor of the minor salivary glands?
Mucoepidermoid Carcinoma.
Smaller the gland = more common the malignant tumors.
148
Bilateral parotid masses?
Lymphoma
Sjogrens
149
Duct of the Parotid Gland
Stensons
150
What is Benign Lymphoepithelial Disease in the Parotid Gland?
Bilateral mixed solid and cystic lesions with diffusely enlarged parotid glands. Painless.
HIV
Sjogrens will be honeycombed appearance of the gland
151
What is Lemierre Syndrome?
Thrombophlebitis of the jugular veins with distant metastatic sepsis (septic emboli in the lungs).
Oropharyngeal infection (pharyngitis, tonsillitis, peri tonsillar abscess), or recent ENT surgery.
152
What is Grisel's Syndrome?
Torticollis with atlanto-axial joint inflammation seen in H&N surgery or retropharyngeal abscess.
153
Displacement of the parapharyngeal space
Anterior = Carotid Mass
Medial = Parotid Mass
Posterior medial = Masticator Space
Lateral = Superficial Mucosal
154
What separates LN levels 1A from 1B?
Anterior belly of digastric
155
What separates LN levels 1B from 2A?
Stylohyoid muscle - posterior submandibular gland
156
Things to know about laryngeal SCC?
Glottic SCC has the best outcome (least lymphatics), and is the MC.
Subglottic is the least common and can be clinically silent until you get nodes.
Fixation of the cords indicates at least a T3 tumor.
Only reliable sign of cricoid invasion is tumor on both sides of the cartilage (irregular sclerotic cartilage can be normal)
Invasion of the cricoid cartilage is a contraindication to al types of laryngeal conservation surgery (cricoid cartilage is necessary for postoperative stability of the vocal cords.
Paraglottic space involvement makes the tumor T3 and "transglottic". Best seen on coronals.
157
What is a Laryngocele associated with?
Tumor - causing obstruction.
158
What is Persistent Hyperplastic Primary Vitreous?
Failure of the embryonic ocular blood supply to regress. Can lead to retinal detachment.
Small eye (microphthalmia) with increased density of the vitreous. No calcification.
159
What is Coat's Disease?
Retinal telangiectasis - results in leaky blood and subretinal exudate. Can lead to retinal detachment.
Young boys and typically unilateral.
NOT CALCIFIED.
160
Globe sizes with lesions?
```
Retinoblastoma - normal size
Coats - Normal size
Toxocariasis - Normal Size
PHPV - Small size (normal at birth)
Retinopathy of prematurity - bilateral small
```
161
MC involved with orbital pseudotumor
Lateral rectus and does NOT spare the myotendinous insertions.
Painful, unilateral.
162
What is an orbital dermoid?
MC benign congenital orbital mass.
Usually superior and lateral arising from the frontozygomatic suture - in the first 10 years of life.
Will have fat.
163
What causes raccoon eyes?
Metastatic neuroblastoma.
Periorbital tumor infiltration with associated proptosis.
164
What does breast cancer mets to the orbit look like?
Will cause a desmoplastic reaction and enopthalmos.
Unlike primary orbital tumors which cause proptosis.
165
MC intra-ocular lesion in an adult?
Melanoma.
Collar button shaped - related to Bruch's membrane.
166
Kids with retinoblastoma after radiation are at increased risk of what?
Osteosarcoma b/c RB suppressor gene (chromosome 13).
167
What is an Orbital Lymphangioma?
Mix of venous and lymphatic malformations. Ill-defined and lack a capsule.
Infiltrative (multi-spatial) involving, pre-septal, post septal, extraconal, and intraconal locations. Fluid-fluid levels. Do NOT increase with Valsalva.
Varix will increase with valsalva - MC cause of spontaneous orbital hemorrhage.
168
Where does the orbital septum originate?
Periosteum of the orbit and inserts in the palpebral tissue along the tarsal plate.
Pre-septal infection = adjacent structures like teeth and face.
Post-septal = paranasal sinuses.
169
What is Dacryocystitis?
Inflammation and dilation of the lacrimal sac.
Well circumscribed round rim enhancing lesion centered in the lacrimal fossa. Obstruction and bacterial infection.
170
Causes of early and late failed back surgery syndrome?
Early:
Epidural abscess
Late:
Epidural fibrosis
Recurrent disk herniation
Arachnoiditis
171
What is an Os Odontoideum prone to and what is it associated with?
Prone to subluxation and instability.
Association with Morquio's syndrome.
```
Orthotopic = position right on top of the dens
Dystopic = fused to the clivus.
```
172
What is Anterior Cord Syndrome?
Motor function and anterior column sensations (pain and temperature) are gone.
Dorsal column (proprioception and vibration) are still intact.
173
What is Central Cord Syndrome?
Old lady with spondylosis or young person with bad extension injury.
Upper extremity deficit is worse than lower (corticospinal tracts are lateral in lower extremity).
174
What is the Terminal Ventricle?
Ventricularis Terminalis
Developmental variant. Don't have uniform involution of the distal spinal cord - get stuck with cyst at the end of the cord
175
What is Currarino Triad?
Anterior Sacral Meningocele
Anorectal Malformation
Sacrococcygeal Osseous Defect (simitar sacrum).
176
Types of Spinal AVMs/AVFs
Type 1: MC type. Dural AVF - single coiled vessel
Type 2: Intramedullary Nidus from anterior spinal artery or posterior spinal artery. Can have aneurysms and can bleed. MC presentation is SAH. Associated with HHT and KTS (other vascular syndromes)
Type 3: Juvenile, very rare, often complex and with terrible prognosis.
Type 4: Intradural perimedullary with subtypes depending on single vs multiple arterial supply. Near the conus.
177
What is Foix Alajouanine Syndrome?
Myelopathy associated with dural AVF.
45 y/o M with lower extremity weakness and sensory deficits. Have prominent vessels. Venous HTN is underlying mechanism.
178
Spine TB mimic
Brucellosis
Cow's milk or farm exposure.
179
Syndromes associated with syrinx
Chiari I and II, Dandy-Walker, Klippel-Feil, and Myelomeningocele.
Other 10% - trauma, tumor, or vascular insufficiency.
180
What is Subacute Combined Degeneration?
B12 deficiency.
Bilateral symmetrically increased T2 signal in the dorsal columns w/o enhancement.
Inverted V sign.
Begins in the upper thoracic region with ascending or descending progression.
181
What is HIV Vacuolar Myelopathy?
Late finding in AIDS patients.
Spinal cord atrophy, T2 high signal symmetrically involving the posterior columns. Looks like subacute combined degeneration.
182
What does Spinal Cord Infarct look like?
Treating aneurysm with stent graft or embolizing bronchial artery.
Owl eye appearance of anterior spinal cord infarct.
183
Causes of spine drop mets?
Medulloblastoma is MC
| Breast is MC systemic tumor (followed by lung and melanoma)
184
How does the corpus callosum form?
Front to back - then rostrum
Genu, body, isthmus, splenium, then rostrum
185
What is Colpocephaly?
Disproportionate prominence of the occipital horns of the lateral ventricles
186
What are CNS lipomas?
Congenital malformations, not true neoplasms.
Tubulonodular type frequently calcifies.
187
What is Anencephaly?
Neural tube fails to close on the cranial end - reduced or absent cerebrum and cerebellum. Hindbrain will be present.
AFP will be elevated, polyhydramnios.
Frog eye appearance
188
What is Iniencephaly?
Deficit of the occipital bones - enlarged foramen magnum. Messed up spines.
Star Gazing Fetus - contorted, makes their face turn upward.
189
What is Arhinencephaly?
No olfactory bulbs and tracts.
Kallmann syndrome (hypogonadism and MR).
190
What is Rhomboencephalosynapsis?
Congenital anomaly of the cerebellum - vermis doesn't develop - just fuse your cerebellum.
Transversely oriented single lobed cerebellum
191
What is Joubert Syndrome?
Molar Tooth appearance of the superior cerebellar peduncles. Small or aplastic cerebellar vermis - absence of pyramidal decussation.
Strong association with retinal dysplasia. Association with multicystic dysplastic kidneys. When seen in combination with liver fibrosis = COACH syndrome.
192
What is Torcular-Lambdoid Inversion?
Seen in Dandy Walker, absent vermis.
