Randomized clinical trials have established a role for CT perfusion in evaluating selected anterior circulation large vessel occlusion patients for endovascular thrombectomy (EVT).
Key takeaways:
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A multicenter retrospective study evaluated perfusion imaging in basilar artery occlusion patients treated with endovascular thrombectomy.
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The study used a Critical Area Perfusion Score based on regions with severe hypoperfusion at Tmax greater than 10 seconds.
- Reperfused patients with CAPS of 3 or less were more likely to achieve favorable functional outcomes at 90 days.
Can perfusion imaging help select BAO patients eligible for EVT?
Dr. Carlo Cereda and co-authors conducted a multicenter retrospective cohort study examining whether perfusion imaging could help identify basilar artery occlusion (BAO) patients more likely to respond favorably to EVT.
Critical Area Perfusion Score to identify BAO patients who could benefit from EVT
The authors noted that standard selection measures such as ischemic core and penumbra volumes are difficult to apply in the posterior circulation because even a small amount of irreversible injury in the midbrain, pons or thalamus can have major clinical consequences.
They hypothesized that BAO patients with fewer regions of severe hypoperfusion, defined as Tmax greater than 10 seconds, would respond more favorably to endovascular reperfusion. The study included 103 BAO patients who underwent perfusion imaging before EVT, with CT and MR perfusion images processed using Rapid software.
A predefined Critical Area Perfusion Score (CAPS) quantified severe hypoperfusion in key posterior circulation regions:
- Cerebellum: 1 point per hemisphere
- Midbrain and/or thalamus: 2 points
- Pons: 2 points
A region was considered positive when the Tmax greater than 10-second lesion measured at least 6 mm in diameter. Patients were classified as favorable when CAPS was 3 or less and unfavorable when CAPS was greater than 3.
BAO patients with limited regions of severe hypoperfusion had a favorable response to EVT.
The study found that reperfused patients with CAPS of 3 or less were more likely to achieve good functional outcomes at 90 days following EVT. The findings suggest that the extent of severe hypoperfusion may provide useful information when evaluating BAO patients for EVT.
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