Interventional Radiology and Stroke Flashcards
1
Q
Recognize the treatment of acute infarcts
A
EARLIER INTERVENTION = GREATER BENEFIT!!
- TPA: Within 4.5 hours after, Extend time window significantly in basilar artery thrombosis
- Reopro: GPIIbIIIa platelet inhibitor often given with TPA
- Mechanical thrombectomy: MERCI, Penumbra
- Off-label devices currently in development: Balloons, Stents
2
Q
Infarction on CT
A
- Focal hypodense area in cortical, subcortical, or deep gray or white matter, following vascular territory, or watershed distribution.
- 1-6 hours: obscuration of gray/white matter contrast and effacement of sulci, or “insular ribbon.”
- 6 hours to 4 days: progressive swelling, hypodensity, structures pushed around
- 4-14 days: return to normal density and volume
- > 14 days: varying degrees of hypodensity and volume loss (ventricles and sulci look bigger as a result of brain volume decrease)
3
Q
Acute Infarction on MRI
A
- Subtle low signal (hypointense) on T1, often difficult to see at the acute stage
- High signal (hyperintense) on spin density and/or T2-weighted and proton density-weighted images starting 8 hours after onset; should follow vascular distribution.
- Mass effect maximal at 24 h
4
Q
Subacute Infarction on MRI
A
Low signal on T1 or high signal on T2-weighted images.
- Follows vascular distribution.
- Revascularization and blood-brain barrier breakdown may cause parenchymal enhancement with contrast agents.
5
Q
Old Infarction on MRI
A
Low signal on T1, high signal on T2.
- Mass effect disappears after 1 month
- Loss of tissue with large infarcts
6
Q
Perfusion CT in the workup of an acute infarct
A
- Inject IV contrast into antecubital fossa
- Continuous imaging at 2-4 locations for about a minute
- Determines amount of blood flow, blood volume, and timing it takes the bolus to reach areas of the brain
- Helps determine whether there is brain penumbra that can be saved
- Need to know this to determine whether patient is a candidate for TPA therapy
7
Q
CT Angiography in the workup of acute infarcts
A
- Inject IV contrast into internal carotid artery
- Thin image sections taken to visualize vascular anatomy
- Helps identify site of occlusion, infarct core, and collateral flow
- Helps determine whether intervention (TPA, MERCI, Penumbra) worked
8
Q
Who is a candidate of TPA
A
Completed Infarct: No TPA
(Increased time to start, increased time to peak, Decreased blood volume)
Brain at Risk: TPA Candidate (Increased time to start, increased time to peak, Normal OR Increased blood volume)