Perfusion computed tomography (CT) allows to evaluate brain perfusion and provides additional information about local cerebral hemodynamics in stroke patients. Twenty-seven patients underwent CT-perfusion in the early acute phase of ischemic stroke. Significant differences between ischemic lesion and contralateral hemisphere on CBF and MTT scans during the first 3 hours after stroke were revealed. In the following 24 h, the differences were seen in all perfusion parameters. CT-perfusion allows to reveal perfusion parameters associated with stroke severity and outcome that is relevant for prescription of reperfusion treatment beyond the boundaries of 3-4.5h "therapeutic window".