Computed Tomography (CT) Perfusion imaging provides a quantitative measurement of regional cerebral blood flow. A perfusion CT study involves sequential acquisition of CT sections during intravenous administration of an iodinated contrast agent. Analysis of the results allows the physician to calculate the regional cerebral blood volume, the blood mean transit time through the cerebral capillaries, and the regional cerebral blood flow.
CT perfusion imaging has been proposed to be used primarily as a method of evaluating patients suspected of having an acute stroke whenever thrombolysis is considered. CT perfusion imaging may provide information about the presence and site of vascular occlusion, the presence and extent of ischemia, and about tissue viability. This information may help the clinician determine whether thrombolysis is appropriate.
Potential advantages of CT perfusion imaging are that it can be performed using standard CT scanners, which are more widely available and it is less invasive than CT angiography. CT perfusion imaging can be performed rapidly, and involves injection of a relatively small amount of contrast agent.