Objective: To compare conventional and automated Alberta Stroke Program Early CT score (ASPECTS) to CT perfusion core volumes to predict functional outcome in acute ischemic stroke patients with successful reperfusion after thrombectomy.
Materials and methods: Patients from the Computed Tomography Perfusion to Predict Response to Recanalization in ischemic Stroke Project (CRISP) study who achieved mTICI 2b or 3 reperfusion were included. Four independent physicians rated and reached consensus on the conventional ASPECT scores of the baseline CT. Automated ASPECT scores were determined with e-ASPECTS software (Brainomix, Oxford, UK). We used RAPID software (iSchemaView, Stanford, USA) to analyze CT perfusion core volumes. Good and poor functional outcome (GFO and PFO) was defined as a score of 0-2 and 4-6 on the modified Rankin Scale (mRS). Predictors of GFO and PFO were obtained by multivariate logistic regression.
Results: We included 156 patients from the CRISP study. Interrater reliability for conventional ASPECTS was excellent (intra-class correlation coefficient 0.77). Median values for conventional ASPECTS, automated ASPECTS, and CT perfusion core volume were 7 (IQR 5-8), 9 (IQR 7-10) and 6.2 ml (IQR 0-17.7). Patients with GFO (59%) had lower baseline NIHSSS, lower rates of diabetes and smaller CTP infarct cores (p < 0.01 for all). Patients with PFO (25%) were older (p < 0.0001), had higher NIHSSS (p = 0.001), higher rates of diabetes (p < 0.0001) and larger CTP infarct cores (p < 0.05). In multivariate analysis CT perfusion core volume was associated with both GFO (OR 0.98; 95%CI 0.96-1.00) and PFO (OR 1.02; 95%CI 1.01-1.04)). Automated ASPECTS was a predictor for GFO (OR 1.26; 95%CI 1.04-1.53) but not PFO. Conventional ASPECTS was not associated with functional outcomes.
Conclusion: In the setting of successful thrombectomy, CTP core volume is a better predictor of functional outcome than either conventional or automated ASPECTS.