Hemorrhagic transformation of ischemic stroke: prediction with CT perfusion.

Abstract

To determine whether admission computed tomography (CT) perfusion-derived permeability-surface area product (PS) maps differ between patients with hemorrhagic acute stroke and those with nonhemorrhagic acute stroke. This prospective study was institutional review board approved, and all participants gave written informed consent. Forty-one patients who presented with acute stroke within 3 hours after stroke symptom onset underwent two-phase CT perfusion imaging, which enabled PS measurement. Patients were assigned to groups according to whether they had hemorrhage transformation (HT) at follow-up magnetic resonance (MR) imaging and CT and/or whether they received tissue plasminogen activator (TPA) treatment. Clinical, demographic, and CT perfusion variables were compared between the HT and non-HT patient groups. Associations between PS and HT were tested at univariate and multivariate logistic regression analyses and receiver operating characteristic (ROC) analysis. HT developed in 23 (56%) patients. Patients with HT had higher National Institutes of Health Stroke Scale (NIHSS) scores (P = .005), poorer outcomes (P = .001), and a higher likelihood of having received TPA (P = .005) compared with patients without HT. Baseline blood flow (P = .17) and blood volume (P = .11) defects and extent of flow reduction (P = .27) were comparable between the two groups. The mean PS for the HT group, 0.49 mL x min(-1) x (100 g)(-1), was significantly higher than that for the non-HT group, 0.09 mL x min(-1) x (100 g)(-1) (P < .0001). PS (odds ratio, 3.5; 95% confidence interval [CI]: 1.69, 7.06; P = .0007) and size of hypoattenuating area at nonenhanced admission CT (odds ratio, 0.4; 95% CI: 0.2, 0.7; P = .002) were the only independent variables associated with HT at stepwise multivariate analysis. The mean area under the ROC curve was 0.918 (95% CI: 0.828, 1.00). The PS threshold of 0.23 mL x min(-1) x (100 g)(-1) had 77% sensitivity and 94% specificity for detection of HT. Admission PS measurement appears promising for distinguishing patients with acute stroke who are likely from those who are not likely to develop HT. http://radiology.rsnajnls.org/cgi/content/full/250/3/867/DC1.