Neuro

Question 1

What imaging modality should be performed first in the setting of head trauma?

Answer 1

CT w/o contrast (+ normal trauma series)

Question 2

Epidural Hematoma

Answer 2

biconvex or lenticular in shape
overlays fracture site
doesn't cross suture lines
typically arterial 
lucid intervals with risk for deterioration and herniation

Question 3

Subdural Hematoma

Answer 3

crescent shaped
tearing for bridging veins
cross suture lines
reflects with arachnoid mater at falx but doesn’t cross

Question 4

Subarachnoid Hemorrhage

Answer 4

between arachnoid and pia mater 
trauma or rupture of an aneurysm
hyperdense areas on the CT within the sulci and the cisterns
best if detected w/n 12hrs on CT 
Feared complication- vasospasm!

Question 5

Intraventricular Hemorrhage

Answer 5

tearing of subependymal veins
collection in lateral ventricles
typically results from corpus collosum injury

Question 6

Intraparenchymal Hemorrhage

Answer 6

trauma, hemorrhagic stroke, a ruptured AVM, or a hemorrhagic neoplasm.

Question 7

The NEXUS Criteria for C-spine imaging

Answer 7

All trauma imaged unless all criteria met:

• No posterior midline c-spine tenderness
• No intoxication
• Normal level of alertness
• No focal neurological deficit
• No clinically apparent painful injuries that might distract from pain of a cervical spine injury

Question 8

Canadian C-Spine Rules for C-spine imaging

Answer 8

Image if  high-risk factors:
-Age >65 years
-"Dangerous mechanism"- MVA 
-Paresthesias in extremities
 Don't image if: 
-Simple rear-end MVA
-Sitting position in ED
-Ambulatory at any time
-Delayed onset of neck pain
-Absence of midline cervical tenderness
-Able to actively rotate neck 45° left and right

Question 9

What is the best modality to look for spinal cord injury or compression?

Answer 9

MRI

Question 10

What is the best modality to look for spinal fractures?

Answer 10

CT

Question 11

Uncal herniation

Answer 11

• medial temporal lobe herniates through the tentorial hiatus
• effacement of the suprasellar
• cranial nerve III palsies

Question 12

Cerebellar tonsillar herniation

Answer 12

• cerebellar tonsils are pushed inferiorly through the foramen magnum
• often seen with posterior fossa masses

Question 13

Best imaging for Diffuse axonal injury ?

Answer 13

MRI GRE or FLAIR are more sensitive and should follow CT for confirmation.

Question 14

Rank from most likely to least likely the locations where berry aneurysms are known to occur.

Answer 14

ACA
PCA
MCA

Question 15

What is the most sensitive examination for detection of acute ischemia?

Answer 15

MRI DWI
(CT doesn't show imaging features of infarct until at least 6 hours)

Question 16

Differential for seizure in immunocompromised patient with history of cerebral aneurysm?

Answer 16

• Toxoplasmosis
• CNS lymphoma
• Neurocysticercosis
• Cerebral metastasis
• Pyogenic abscess
• Aneurysm recurrence

Question 17

MRI findings which favor toxoplasmosis include:

Answer 17

• Multiple lesions
• Abundant edema
• Target Enhancement
• Deep gray matter (caudate nucleus, basal ganglia) involvement
  (Typically due to reactivation of latent disease)

Question 18

MRI findings suggestive of PCNSL include:

Answer 18

• Solitary lesion
• Subependymal enhancement
• Encasement of the ventricles
• Hypointensity of the core on T2-weighted imaging

Question 19

MR Spect Distinguishing cerebral lymphoma from toxoplasmosis

Answer 19

Malignancy=

1) HIGHT Choline/Creatine rati
2) Low N-Acetyl-Aspartate/Creatine ratio