Comparative studies of computed tomography and of regional cerebral blood flow (rCBF) by means of the intracarotid xenon-133-clearance method were performed in 25 stroke patients. The relationships between an infarction in CT and disturbances of rCBF, between a normal CT in stroke cases and focal changes of CBF, and between the luxury perfusion syndrome in the rCBF study and contrast enhancement of an infarct in CT are demonstrated and discussed.