Computed tomography perfusion-defined ischemic core predicts functional outcome after basilar artery thrombectomy

Purpose This study aimed to determine the optimal threshold for computed tomography perfusion (CTP)-defined ischemic core in patients with basilar artery occlusion (BAO) that predicts functional outcome. Methods A retrospective analysis was conducted on BAO patients who underwent endovascular thrombectomy at our stroke center between January 2018 and March 2024. Ischemic core was estimated using following thresholds: cerebral blood flow (CBF) < 10 or 15 mL/100 g/min by Syngo.via, cerebral blood volume < 1.2 mL/100 mL by Syngo.via, and time to maximum (Tmax) > 10 s by RAPID. A favorable functional outcome was defined as a modified Rankin Scale score of 0–3 at 90-day post-onset. The Posterior Circulation Alberta Stroke Program Early computed tomography Score (pc-ASPECTS) was semi-quantified to assess ischemic changes. Statistical analysis included intraclass correlation coefficient (ICC) and receiver operating characteristic analyses. Results A total of 85 patients were enrolled, and 39 (45.9%) had a favorable functional outcome. The ICC for pc-ASPECTS based on four core approaches between junior and senior observers ranged from 0.90 to 0.96. For the classification of favorable outcome, the volume and pc-ASPECTS core estimation approach (CBF < 10 mL/100 g/min by Syngo.via) had the best performance, with the largest area under the curve of 0.86 [(95% confidence intervals, 0.78–0.94); p < 0.001] and 0.87 [(95% confidence intervals, 0.80–0.94); p < 0.001], with a cut-off value of ≤ 2.2 (78.3%% sensitivity, 84.6% specificity), and ≥ 7 (92.3% sensitivity, 65.2% specificity). Conclusion In BAO patients following successful recanalization, the volume and pc-ASPECTS core estimation approach (CBF < 10 mL/100 g/min by Syngo.via) demonstrated the strongest predictive value for favorable functional outcomes.