Interventional Radiology and Stroke

Question 1

Recognize the treatment of acute infarcts

Answer 1

EARLIER INTERVENTION = GREATER BENEFIT!!

1. TPA: Within 4.5 hours after, Extend time window significantly in basilar artery thrombosis
2. Reopro: GPIIbIIIa platelet inhibitor often given with TPA
3. Mechanical thrombectomy: MERCI, Penumbra
4. Off-label devices currently in development: Balloons, Stents

Question 2

Infarction on CT

Answer 2

• 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)

Question 3

Acute Infarction on MRI

Answer 3

• 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

Question 4

Subacute Infarction on MRI

Answer 4

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.

Question 5

Old Infarction on MRI

Answer 5

Low signal on T1, high signal on T2.

• Mass effect disappears after 1 month
• Loss of tissue with large infarcts

Question 6

Perfusion CT in the workup of an acute infarct

Answer 6

• 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

Question 7

CT Angiography in the workup of acute infarcts

Answer 7

• 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

Question 8

Who is a candidate of TPA

Answer 8

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)