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Flashcards in imaging Deck (20):
1

what is the imaging test of choice in suspected acute stroke?

non-contrast CT

2

4 CT signs of stroke

1 - dense middle cerebral artery (MCA)
2 - loss of grey-white differentiation
3 - loss of insular ribbon
4 - effacement of sulci

2-4 are signs of cytoxic edema

3

how long can a CT still be normal after an acute stroke?

6-24 hours

4

why is the MCA dense in acute stroke?

clotted blood in the vessel

5

what is tPA?

tissue plasminogen activator, treatment for acute stroke within 3 hour window, with only precluding factor being hemorrhage on a CT

6

what can preclude tPA treatment?

hemorrhage on a CT

7

what is the gold standard for identifying dead brain tissue after a stroke?

- brightness maintained for 10-14 days on diffusion imaging MRI indicates irreversible injury

8

potential false positives for dead brain tissue

abscess, hemorrhage, MS

9

common characteristics of epidural hematoma

- 85-95% underlying fracture
- won't cross bone sutures
- usually at site of impact
- biconvex
- better prognosis than others

10

management of EDH

- if less than 30cc's, thinner than 15mm, less than 5mm midline shift, glascow coma scale greater than 8, manageable without operation
- 30cc's should be evacuated no matter what
- GSC less than 9 with anisocoria (uneven pupils), evacuate ASAP

11

common characteristics of SDH

- crescentic
- can be coup or countercoup
- midline shift and thickness important
- worse prognosis than EDH

12

management of SDH

- thickness greater than 10mm or midline shift greater than 5mm should be evacuated
- GCS less than 9, ICP should be monitored
- decrease in GCS by 2 or more, increased ICP, or fixed and dilated or asymmetric pupils are indications for evacuation even if thickness and midline shift criteria are not met

13

where is the midline shift measured?

- foramen of monro
- (A/2) - B

14

what is the #1 cause of SAH?

trauma

15

treatment of SAH?

no specific treatment

16

where are you most likely to find hematoma due to contusion?

anterior/inferior frontal
anterior temporal

17

contusion hematoma gets bigger and more pronounced over what period of time?

2-3 days

18

pathophys of diffuse axonal injury

most axons not injured, but cascade begins that leads to cell death over 24 hours

19

where find diffuse axonal injury?

grey/white interface, midbrain, corpus callosum

20

CT vs MRI in trauma

- get CT first because it identifies all surgically important lesions
- MRI is better at detecting SDH, EDH, contusion, axonal injury (important for unexplained continued deficits)