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Flashcards in imaging Deck (20)
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1
Q

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

A

non-contrast CT

2
Q

4 CT signs of stroke

A

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
Q

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

A

6-24 hours

4
Q

why is the MCA dense in acute stroke?

A

clotted blood in the vessel

5
Q

what is tPA?

A

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

6
Q

what can preclude tPA treatment?

A

hemorrhage on a CT

7
Q

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

A
  • brightness maintained for 10-14 days on diffusion imaging MRI indicates irreversible injury
8
Q

potential false positives for dead brain tissue

A

abscess, hemorrhage, MS

9
Q

common characteristics of epidural hematoma

A
  • 85-95% underlying fracture
  • won’t cross bone sutures
  • usually at site of impact
  • biconvex
  • better prognosis than others
10
Q

management of EDH

A
  • 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
Q

common characteristics of SDH

A
  • crescentic
  • can be coup or countercoup
  • midline shift and thickness important
  • worse prognosis than EDH
12
Q

management of SDH

A
  • 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
Q

where is the midline shift measured?

A
  • foramen of monro

- (A/2) - B

14
Q

what is the #1 cause of SAH?

A

trauma

15
Q

treatment of SAH?

A

no specific treatment

16
Q

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

A

anterior/inferior frontal

anterior temporal

17
Q

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

A

2-3 days

18
Q

pathophys of diffuse axonal injury

A

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

19
Q

where find diffuse axonal injury?

A

grey/white interface, midbrain, corpus callosum

20
Q

CT vs MRI in trauma

A
  • 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)