Computed Tomography-Based Imaging Scores in Basilar Artery Occlusions: A Comparison of Predictive Abilities for Functional Outcomes.

BACKGROUND: Posterior circulation large-vessel occlusion strokes have significant morbidity and mortality, but patient selection for acute interventions remains understudied. Multiple computed tomography (CT)-based scores exist, including the CT perfusion-based critical area perfusion score (CAPS), CT angiography-based basilar artery treatment management and posterior circulation CT angiography scores, and CT angiography source image or noncontrast CT-based posterior circulation Alberta Stroke Program Early CT Score, but their predictive values for long-term outcomes after thrombectomy have not been directly compared. METHODS: We conducted a retrospective multicenter cohort study of patients with basilar artery occlusions treated with endovascular thrombectomy. Four CT-based scores were assessed: posterior circulation Alberta Stroke Program Early CT Score, basilar artery treatment management score, posterior circulation CT angiography score, and CAPS. The primary outcome of interest for the study was a favorable functional outcome at 3 months (modified Rankin Scale score, 0-3). We calculated sensitivity, specificity, positive and negative predictive values, and generated receiver operating characteristic curves measuring area under the curve (AUC), which were compared with nonparametric methods. RESULTS: Ninety-eight patients were included for analysis, with an average age of 64.9 ± 15.6 years. The median National Institutes of Health Stroke Scale score was 13.5 (interquartile range, 7.0-23.0). AUC values were highest for the CAPS (AUC, 0.72 [95% CI, 0.63-82]) and lowest for the posterior circulation CT angiography score (AUC, 0.57 [95% CI, 0.45-0.68]; P=0.019). There was a trend toward the CAPS outperforming the basilar artery treatment management score (AUC, 0.66 [95% CI, 0.55-0.77]) and posterior circulation Alberta Stroke Program Early CT Score (AUC, 0.63 [95% CI, 0.52-0.75]) though this was not statistically significant (P=0.29 and P=0.23, respectively). CAPS ≤3 demonstrated 100% sensitivity and negative predictive value (95% CI, 92.6-100.0%; 95% CI, 75.7-100.0%, respectively) for good outcome but had low specificity (24.0% [95% CI, 14.3-37.4]). CONCLUSIONS: The CT perfusion-based CAPS had the best performance for predicting good functional outcome at 3 months and had high sensitivity and negative predictive values though our finding is limited by the small number of patients who had CAPS >3. The CAPS should be validated in prospective studies.