RITE Images 2002

Question 1

Answer 1

Demyelination – MS

Gray hue b/c of loss of myelin

Question 2

Answer 2

Wet keratin – adamantinomatous craniopharyngioma

Question 3

Answer 3

Subacute form of AIDS

Axial T2 weighted image showing diffuse high signal intensity throughout white matter

Question 4

Answer 4

Aneurysm – sagittal T1 flow void

Diff dx – pituitary adenoma, meningioma, aneurysm

Question 5

Answer 5

Radiation injury vs. recurrent brain tumor -> do FDG PET or Thallium SPECT to differentiate tumor from radiotherapy injury

**The lesion crosses ACA & MCA vascular boundaries & spares the cortex -> not a stroke!

Question 6

Answer 6

Ragged red fibers – usually seen in mitochondrial myopathies
Kearns-Sayre myopathy

Werdnig-Hoffman – motor neuron
Duchenne’s – Dystrophin
Central core myopathy – genetic

Question 7

Answer 7

Open ring sign w/ enhancement on GAD -> Demyelinating lesion

White matter affected

**Closed rings – GBM, lymphoma, abscess

Question 8

Answer 8

Lesion lies in the MOTOR cortex -> frontal lobe

Question 9

Answer 9

SDH

Question 10

Answer 10

Spinal stenosis – narrowing of dural sac on AP & lateral contrast myelogram

Question 11

Answer 11

Pachygyria – cortex is thick

Frontal lobe cortex is flat, white matter in that area doesn’t have the interdigitation

Occurs during 2nd trimester – neuronal migration

Question 12

Answer 12

No middle cerebral artery

Question 13

Answer 13

VP shunt for NPH

Question 14

Answer 14

Optic nerve lesion extending into anterior chiasm -> temporal field defect in contralateral eye

Question 15

Answer 15

Vasculitis – affected small & medium sized vessels “beads on a string”

Question 16

Answer 16

Negri bodies - seen in rabies

Question 17

Answer 17

Subpial corpora amylacea – polyglucosan bodies accumulate w/ age in astrocyte cytoplasmic processes

Question 18

Answer 18

Chiasmal glioma

It does NOT arise from the sella

No cystic region or area of signal void to suggest craniopharyngioma

Question 19

Answer 19

Multiple brain abscesses

Irregular Ring enhancing; mass effect

(Post-Gad images)

Not hamartomas b/c they would have a central high signal intensity on T1

Question 20

Answer 20

Herring bodies in neurohypophyseal tissue;

• Axonal storage sites for oxytocin & vasopressin

Question 21

Answer 21

Cyst is contiguous w/ 4th ventricle resulting from surgical excision of cerebellar astrocytoma

Hemangioblastomas – 2 of 3 which may contain cysts

Question 22

Answer 22

GBM – post GAD, intense homogeneous, nodular, ring-like enhancement, encloses a central isointense necrotic core & delineates the gross tumor margin

Question 23

Answer 23

Myxopapillary ependymoma

Question 24

Answer 24

Focal conduction block of CMAP from demyelination in CIDP

Decreased amplitudes w/o axonal involvement

Question 25

Answer 25

Intraparenchymal hematoma – high density mass w/ edema

Question 26

Answer 26

**Myokymic discharges** – rhythmic & can be seen as singlets or multiplets; sometimes assoc w/ _K+ channel antibodies_

Question 27

Answer 27

**Metachromatic leukodystrophy (MLD)** – \*white matter demyelination w/ spared U-fibers! Confluent periventricular demyelination also can be adrenoleukodystrophy & Krabbe’s

Question 28

Answer 28

Agenesis of corpus callosum

Question 29

Answer 29

**AD SCA Type 6** –pure cerebellar atrophy predominantly superior vermis \*NO pontine atrophy to suggest olivo-ponto-cerebellar atrophy & Machado Joseph disease; \*NO downward displacement of cerebellar tonsils & posterior fossa is not smaller than normal -\> r/o ACM \*NO subarachnoid cyst b/c no cerebellar compression

Question 30

Answer 30

A-comm artery aneurysm

Question 31

Answer 31

**Astrocytoma** – infiltrating neoplasm – b/c the mass in the parasagittal parietal & occipital lobes extends into splenium of CC \*NOT PCA infarct b/c it wouldn’t cross midline \*NOT acute hematoma b/c it would be hypointense on both T1 & T2

Question 32

Answer 32

Non-communicating/obstructive hydrocephalus

Question 33

Question 34

Answer 34

Thrombus in Vein of Galen & Straight sinus – abnormal hyperintensity on T1 & axial proton density images; hemorrhagic infarction in B thalami

Question 35

Answer 35

B frontal contusions w/ slight orange tinge 2ndary to presence of residual hemosiderin-laden macrophages

Question 36

Answer 36

Lacunar infarcts

Question 37

Answer 37

Oligodendrogliomas

Question 38

Answer 38

Reversible posterior leukoencephalopathy – found in pts w/ malignant HTN Found in 85% of patients studied w/in 72 hrs after onset of sx

Question 39

Answer 39

Spinal stenosis - Constricted spinal canal 2ndary to degenerative facet joint disease \*no disc herniation or synovial cyst present

Question 40

Answer 40

Herniated disc

Question 41

Answer 41

Myxopapillary ependymoma

Question 42

Answer 42

**AVM** – need to follow up w/ cerebral angiogram \*this is a contrast enhanced CT showing a large lobulated densely enhancing structure medial to the Sylvian fissure w/ a large serpiginous structure leading from lesion posteriorly towards the vein of Galen -\> need to follow up w/ angiogram

Question 43

Answer 43

Communicating hydrocephalus

Question 44

Answer 44

**Discitis** -pt had documented E. faecalis osteomyelitis affecting L2/L3; ring enhancing

Question 45

Answer 45

Wernicke’s encephalopathy / thiamine deficiency; mammillary bodies congested & discolored

Question 46

Answer 46

**Toxoplasmosis** – ring enhancing, multiple & located in deep central grey nuclei or lobar G/W jxn. - Iso to hypointense on T1 & hyperintense on T2 w/ mass effect & edema - You need the question stem

Question 47

Answer 47

**Lambert eaton syndrome** – incremental response cof CMAP of \> 200% following exercise w/ or w/o decrement on repetitive stimulation

Question 48

Answer 48

**Creutzfeldt astrocyte** – multiple small nuclei (micronuclei) & abundant eosinophilic cytoplasm \***seen in demyelinating disease**

Question 49

Answer 49

Germinoma – most common pineal region tumor

Question 50

Answer 50

**Sagittal sinus venous thrombosis** – infarction w/ hemorrhage over an area of extensive cortex & in underlying white matter \*venous thrombosis assoc w/ hypercoaguable state & severe dehydration

Question 51

Answer 51

Carbon Monoxide poisoning

Question 52

Answer 52

**Subdural hematoma** \*pt presented w/ symptoms after recovery from anesthesia & is bright on T1 & T2; well known complication of spinal anesthesia & LP

Question 53

Answer 53

Leptomeningeal melanocytes

Question 54

Answer 54

DNET Dysembryoplastic neuroepithelial tumor

Question 55

Answer 55

**Suppurative ventriculitis** – abnormal ependymal enhancement & CSF hyperdense, white matter w/ marked edema

Question 56

Answer 56

MS

Question 57

Answer 57

**meningothelial (arachnoid) cell cluster** in the fibrovascular stroma of choroid plexus -\> *occasionally give rise to meningiomas (intraventricularly)*

Question 58

Answer 58

**Pleomorphic xanthoastrocytoma** – large cyst w/ mural nodule; - usually found in temporal or parietal lobes - Surrounded w/ minimal hemosiderin rim

Question 59

Answer 59

**Vein of galen aneurysm** – congenital anomaly

Question 60

Answer 60

**Metastatic disease** – large mass lesion filling right orbit, compressing & deforming posterior margin of globe; lateral wall of maxilla is destroyed & is assoc w/ soft tissue mass

Question 61

Answer 61

**Neurofibroma or meningioma** -\> surgical removal Do not need to do CT myelogram \*intradural extramedullary

Question 62

Answer 62

**Subacute hemorrhage** 2ndary to **infarct** (not AVM b/c it would have been bigger) \*high signal on T1

Question 63

Answer 63

**Locus ceruleus** – source of NE projections

Question 64

Answer 64

**Pornecephalic cyst** – lesion partially covered by arachnoid & extends from SAS to ventricular system; smooth walled & surrounded by abnormal radially oriented gyri

Question 65

Answer 65

**Hyper-dense MCA sign** - Acute thrombosis of LMCA – acute MCA infarction (also look for subtle L cerebral sulcal effacement, hypodensity on L side) Hyperdensity – due to either calcific or hemorrhagic components of acute plaque

Question 66

Answer 66

**Chronic HSV encephalitis** Encephalomalacia in both temporal lobes; can have cystic changes Hyperintensity in temporal lobes

Question 67

Answer 67

**Neurofibrally tangle** – intraneuronal intracytoplasmic inclusion composed of paired helical filaments AD, PD, PSP, Down’s, PD complex of Guam, post-encephalitic Parkinsonism

Question 68

Answer 68

**SDH** – no need for further testing à craniotomy now!

Question 69

Answer 69

**MS plaques** – focal demyelination Not epyndemoma à you’d see focal mass w/ cord enlargement

Question 70

Answer 70

Hematoma – 2 weeks or more in age \*if you see bright on T1 & rim w/ bright on proton density weighted images (b/c of hemosiderin in macrophages surrounding hematoma) --\> methemoglobin

Question 71

Answer 71

* *Centrotemporal spikes** - * *Benign rolandic epilepsy of childhood;** clonic movements of face & hand that often progress to more generalized seizure

Question 72

Answer 72

Proximal internal carotid artery has a rounded stump w/ no distal flow -\> **occlusion** b/c of atherosclerosis

Question 73

Answer 73

String of beads -\> **Fibromuscular dysplasia (FMD)** Characteristically FMD extends from C1-2 to entrance of ICA into petrous carotid canal; 1/3 are assoc. w/ intracranial aneurysms Common patients are young females (age 25-50).

Question 74

Answer 74

**Meningioma** – intradural, extramedullary \*ependymoma, astrocytoma & hemangioblastomas – intramedullary lesions

Question 75

Answer 75

**Arachnoid cyst** – (lesion @ tip of L temporal lobe) -\> spares cortical ribbon & extraaxial -\> r/o head trauma or HSV; the **lesion looks like CSF**

Question 76

Answer 76

**Dandy Walker Malformation** – no vermis , 4th ventricle connects w/ cisterna magna, posterior fossa enlarged

Question 77

Answer 77

Ependymoma – perivascular pseudorosettes

Question 78

Answer 78

**Onset latency** in sensory nerve action potential; initial positivity is the AP passing beneath the active recording electrode

Question 79

Answer 79

**Jitter** on single fiber EMG -\> disease in neuromuscular transmission (**MG**) & denervating neuropathy (**ALS**) ;

Question 80

Answer 80

Cervical portion of carotid -\> C – petrosal segment of carotid artery -\> cavernous portion A – P-comm B – distal ICA D – ACA E – A-comm

Question 81

Answer 81

A – sylvian/lateral fissure / circular sulcus region – separates frontal & temporal lobes B – trigone /atrium of lateral ventricle C – genu of corpus callosum D – frontal paranasal sinus E – subcutaneous fat