Flashcards in imaging Deck (20)
what is the imaging test of choice in suspected acute stroke?
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
how long can a CT still be normal after an acute stroke?
why is the MCA dense in acute stroke?
clotted blood in the vessel
what is tPA?
tissue plasminogen activator, treatment for acute stroke within 3 hour window, with only precluding factor being hemorrhage on a CT
what can preclude tPA treatment?
hemorrhage on a CT
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
potential false positives for dead brain tissue
abscess, hemorrhage, MS
common characteristics of epidural hematoma
- 85-95% underlying fracture
- won't cross bone sutures
- usually at site of impact
- better prognosis than others
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
common characteristics of SDH
- can be coup or countercoup
- midline shift and thickness important
- worse prognosis than EDH
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
where is the midline shift measured?
- foramen of monro
- (A/2) - B
what is the #1 cause of SAH?
treatment of SAH?
no specific treatment
where are you most likely to find hematoma due to contusion?
contusion hematoma gets bigger and more pronounced over what period of time?
pathophys of diffuse axonal injury
most axons not injured, but cascade begins that leads to cell death over 24 hours
where find diffuse axonal injury?
grey/white interface, midbrain, corpus callosum