Abstract Body: Introduction: Imaging features are increasingly relevant for predicting response to endovascular treatment in acute ischemic stroke (AIS) patients. Collateral status is a well-documented marker of reperfusion and mortality in patients with large vessel occlusion (LVO) anterior circulation strokes, which account for approximately one-third of AIS. There is ongoing investigation into optimal collateral status determination, with single and multiphase computed tomography angiography (mCTA) and CT perfusion parameters under consideration. To assess the utility of these parameters, we evaluated their association with the American Society of Interventional and Therapeutic Neuroradiology (ASITN) collateral score standard on digital subtraction angiography (DSA).

Methods: We retrospectively evaluated AIS patients treated at our institution between January 2017 and January 2023. Inclusion criteria were: (i) CTA-confirmed anterior circulation LVO; (ii) diagnostic CT perfusion was performed; (iii) mechanical thrombectomy was attempted with documented DSA collateral score. Modified Treatment in Cerebral Ischemia (mTICI) score was used to determine reperfusion status, with mTICI > 2b considered successful. Univariate and multivariate logistic regression analyses were conducted to determine associations of demographic/clinical factors and collateral status with ASITN and reperfusion status.

Results: A total of 311 patients (mean age 67.35 ± 16.37, 57.4% female) met inclusion criteria. On univariate analysis, PM2 occlusion site (p=9.78E-7), Alberta Stroke Programme Early CT Score (p=0.006), mCTA (p=1.82E-10), cortical vein opacification score (p=4.18E-7), and clot burden score (CBS, p=3.01E-13) were associated with ASITN score of three or greater, signifying complete collateral flow. On multivariate regression adjusted for race, occlusion site, radiologic features, and admission NIH stroke score, PM2 occlusion site (aOR 1.19, p=0.049), mCTA (aOR 3.59, p=6.03E-5), and CBS (aOR 1.37, p=0.03) were associated with ASITN ≥ 3 (Table 1). No radiologic features were associated with successful reperfusion (Table 2).

Conclusion: Multiphase CTA and clot burden score show a stronger association with favorable DSA collateral scores than do CT perfusion parameters, including cerebral blood volume and hypoperfusion intensity ratio. Further studies are needed to evaluate these measures in outcome prediction to aid clinical decision-making for AIS patients with anterior circulation LVOs.