Computed tomography (CT) perfusion imaging is a technique for the measurement of cerebral blood flow, cerebral blood volume, and time-to-peak or mean transit time. The technique involves the administration of a single-bolus dose of iodinated contrast material, followed by spiral CT imaging during the passage of the contrast bolus through the cerebral vasculature. CT perfusion is a fast and inexpensive brain imaging modality for use in the management of patients with various neurological disorders, ranging from acute stroke to subarachnoid hemorrhage. This article reviews the technique of CT perfusion and presents several illustrative cases in which this imaging modality was used effectively in the critical care of patients with neurological disorders. Copyright © 2005 Humana Press Inc. All rights of any nature whatsoever are reserved.