Hemorrhagic transformation of ischemic stroke: prediction with CT perfusion

Abstract

Purpose: 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.

Materials and methods: 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.

Results: 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.

Conclusion: Admission PS measurement appears promising for distinguishing patients with acute stroke who are likely from those who are not likely to develop HT.

Supplemental material: http://radiology.rsnajnls.org/cgi/content/full/250/3/867/DC1.