Value of Perfusion Computed Tomography in Acute Ischemic Stroke: Diagnosis of Infarct Core and Penumbra

Purpose: This study aimed to perform an evaluation of 4 perfusion computed tomographic (PCT) parameters (relative cerebral blood flow, cerebral blood volume, mean transit time [MTT], and delay time [DT]) in a series of patients with acute ischemic stroke to find optimal parameters to predict infarct core and penumbra. Methods: Twenty-six patients with symptoms suggesting stroke less than 7 hours from onset were enrolled in this study. They all underwent admission and 24-hour PCT and a 24-hour diffusion-weighted imaging. Perfusion computed tomographic maps were assessed for relative reduced cerebral blood flow and cerebral blood volume and increased MTT and DT. Receiver operating characteristic curve analysis was performed to locate the optimal threshold for each parameter, using diffusion-weighted imaging as the gold standard. Results: The PCT parameter that most accurately describes the penumbra is the relative MTT of 150% or greater (area under the curve, 0.827; 95% confidence interval, 0.826-0.827), whereas the parameter that most accurately describes the infarct core is the relative DT of +2.0 seconds or greater (area under the curve, 0.879; 95% confidence interval, 0.878-0.879). Conclusions: The optimal parameters to define the infarct core and the penumbra are relative DT (>=+2.0 seconds) and relative MTT (>= 150%).