Abstract TP40: Prediction of a Small DWI Lesion Using Single Phase Collateral Score and Noncontrast CT ASPECT Score

Introduction and Hypothesis: Small initial DWI lesion volume (≤70 mL) is a strong predictor of favorable outcome post i IA thrombectomy and has been used for patient selection in multiple clinical trials. We sought to investigate if collateral and/or CT ASPECT scores could predict a small DWI lesion volume. Methods: We included 130 consecutive patients with CTA showing ICA and/or proximal MCA occlusions who underwent DWI within 8 hours of stroke onset. DWI lesion volumes were dichotomized to small (≤70mL) and large (>70ml). Collateral vessels were categorized to 5 groups: 0=none, 1=minimal, 2=less than 50%, 3=more than 50%, 4=equal and 5=more than the contralateral side. Logistic regression, ROC curve analyses and weighted Kappa test were performed. Results: In 130 patients, 62 female (48%), the average values (mean±SD) were: age 70±17 years, NIHSS 16±6, DWI volume 59±65 mL, time after stroke onset 4.4±1.8 hours, CT ASPECT score 6±2 and collateral score 3±1. Time, age, gender, or occlusion site (ICA vs MCA) were not independent predictors of a small DWI volume with p values all >0.05. Collateral score (OR 6.32, P Conclusion: Collateral score alone or combined with ASPECTS can predict a small DWI lesion volume with high specificity. However, sensitivity is relatively low and inter-rater agreement is fair. These findings should be considered when DWI is not available to select patients for IA therapy.