Imaging Nervous System

Question 1

gray vs white on CT

Answer 1

gray- slightly brighter

white-duller because fat in myelin

Question 2

hypodense lesions

Answer 2

edema
mass
tissue loss

Question 3

hyperdense

Answer 3

mass
calcification
hemorrhage

Question 4

intraaxial brain lesion

Answer 4

takes up space in brain parenchyma
ventricle often smaller
overlying CSF spaces are compressed

Question 5

extraaxial brain lesion

Answer 5

widened CSF space; brain pushed
dark spot-cortical vein
no edema

Question 6

cytotoxic edema

Answer 6

cell death in cortex
cortex becomes less dense
lose gray-white differentiation
–>stroke

Question 7

vasogenic edema

Answer 7

leaky capillaries
edema spreads in white matter
accentuates gray-white differentiation
etiology-tumor, inflam disease, HTN

Question 8

4 CT signs of stroke

Answer 8

CYTOTOXIC EDEMA

-dense middle cerebral artery
loss of gray-white differentation
loss of insular ribbon
effacement of sulci

Question 9

neurons cease to fx at

Answer 9

20ml/min/100g tissue, but are still viable

Question 10

MRI technique that will demonstrate acute strokes

Answer 10

diffusion imaging

Question 11

where is CSF located?

Answer 11

subarachnoid space

Question 12

subdural hematoma is typically

Answer 12

tearing of bridging veins

Question 13

midline shift

Answer 13

at level of foramen monroe

5 mm of shift warrants surgery

Question 14

1 cause of subarachnoid hematoma

Answer 14

trauma

Question 15

contusion

Answer 15

damaged blood vessels as a result of a blow

Question 16

diffuse axonal injury

Answer 16

shear injury of axons

CT intially normal (because axons not directly injured- cascade injures)