Visual Alberta stroke program early computed tomography score versus RAPID-AI perfusion in predicting outcome after late-window thrombectomy

Abstract

Purpose

To evaluate the prognostic utility of visual Alberta stroke program early computed tomography score (ASPECTS) and perfusion parameters obtained from automated RAPID-AI software in patients undergoing mechanical thrombectomy (MT) beyond 6 hours from stroke onset.

Methods

We retrospectively analyzed 86 patients with anterior circulation large vessel occlusion who underwent non-enhanced computed tomography (NECT), multiphase computed tomography angiography, and computed tomography perfusion within 6–24 hours before thrombectomy. Visual ASPECTS (assessed by junior doctor), RAPID-ASPECTS, and RAPID-CTP parameters (ischemic core volume, penumbra, and mismatch ratio) were recorded. The primary outcome was 90-day functional independence (modified Rankin Score 0-2). Multivariable logistic regression and receiver operating characteristic analysis were used to identify independent predictors.

Results

Visual ASPECTS was significantly associated with a favorable outcome (area under the curve = 0.709; optimal cut-off ≥ 6), while no perfusion-derived parameters reached statistical significance. In multivariable analysis, only visual ASPECTS (OR 0.083, 95% CI: 0.033–0.133; p = 0.001), hypertension (OR 0.252, 95% CI: 0.053–0.452; p = 0.014), and symptomatic intracranial hemorrhage (OR 0.634, 95% CI: 0.303–0.964; p < 0.001) remained independent predictors. Agreement between visual and RAPID-ASPECTS was moderate (intraclass correlation coefficient 0.67; 95% CI: 0.49–0.80; p < 0.001), but poor when dichotomized at the ≥ 6 threshold (Cohen's kappa κ = 0.18, p < 0.001).

Conclusion

Visual ASPECTS outperformed perfusion-derived metrics in predicting clinical outcomes after late-window thrombectomy. These findings support the continued relevance of NECT and expert visual scoring, particularly in settings where perfusion imaging may be limited or inconsistent.