In a consecutive group of 56 stroke patients the regional cerebral blood flow was measured within 84 hours after stroke. A 254 multidetector scintillation camera and the intracarotid Xenon-133 injection method was used to study rCBF. Typical rCBF-patterns are described and compared to the findings on CT-scan. According to these studies focal brain areas exposed to ischemia appeared in 3 different forms; 1) As an ischemic area surrounded by a hyperemic borderzone, seen in areas with arterial occlusion and infarction on CT-scan. 2) As a pronounced hyperemic area without associated ischemia located in areas of infarction (seen on CT-scan) without arterial occlusion. This form is presumably due to arterial recanalization and reperfusion in an established infarct. 3) As a pronounced focal hyperemia also without ischemia, located in normal CT-areas without arterial occlusion. This form is probably due to recanalization of an occluded artery shortly after occlusion without development of infarction.