Permeability measures predict hemorrhagic transformation after ischemic stroke

Abstract

Objective: We sought to examine the diagnostic utility of existing predictors of any haemorrhagic transformation (HT) and compare them to novel perfusion imaging permeability measures in ischemic stroke patients receiving alteplase only. Methods: A pixel-based analysis of pre-treatment CT perfusion (CTP) was undertaken to define the optimum CTP permeability thresholds to predict the likelihood of HT. We then compared previously proposed predictors of HT using regression analyses and receiver operator characteristic curve analysis to produce an Area Under the Cure (AUC), and compared AUCs using Chi Square analysis. Results: From 5 centres, 1407 patients were included in this study, 282 had HT. The cohort was split into a derivation (1025, 70% patients) and validation cohort (382 patients or 30%). The E permeability map at a threshold of 30% relative to contralateral had the highest AUC at predicting any HT (derivation AUC 0.85, 95% CI, 0.79-0.91, validation AUC 0.84, 95% CI, 0.77-0.91). The AUC improved when permeability was assessed within the acute perfusion lesion for the E maps at a threshold of 30% (derivation AUC 0.91, 95% CI, 0.86-0.95, validation AUC 0.89, 95% CI, 0.86-0.95). Previously proposed associations with HT and PH showed lower AUC values than the permeability measure. Interpretation: In this large multi-centre study, we have validated a highly accurate measure of HT prediction. This measure may be useful in clinical practice to predict haemorrhagic transformation in ischemic stroke patients before receiving alteplase alone.