Bilateral Reduction of Hemispheric Blood Flow in Patients With Unilateral Cerebral Infarction

Abstract

Bilateral hemispheric blood flow was determined by the intravenous RISA technique in patients with unilateral cerebral infarction. Of all 29 patients, bilateral reduction of cerebral blood flow (CBF) was demonstrated in 13, of whom hemispheric vascular resistance was significantly increased and arm-to-brain circulation time prolonged. In these cases with bilateral subnormal CBF, blood flow on the noninfarcted side tended to increase if the patients were conscious at the time of onset, whereas it remained unchanged even 77 days following stroke if their consciousness was impaired. The already lowered blood flow on the infarcted hemisphere, however, did not increase for a relatively long period of time after the onset. It appears that bilateral reduction of CBF in patients with unilateral infarction is primarily caused by diffuse cerebral vascular changes and some additional systemic circulatory disorder. The possibility of other factors participating is also discussed.