The evaluation of the cerebral hemodynamics in ischemic stroke by the intravenous injection of hippuran ¹³¹I

The mode transit time through each cerebral hemisphere of hippuran mI injected intravenously may furnish valuable information on cerebral hemodynamics in stroke patients. The cerebral circulation was evaluated by this method in 55 patients suffering from an ischemic cerebrovascular accident involving one hemisphere. In patients suffering from an acute completed stroke, the mode transit time of hippuran I3, l was significantly prolonged in the involved hemisphere. No statistically significant changes in the mode transit time were found in patients suffering from transient ischemic attacks. In patients suffering from old completed ischemic strokes, the mode transit time was found to be shorter in the involved hemispheres in the majority of the patients suffering from complete occlusion of the internal carotid artery. This finding may be explained by an intracerebral steal phenomenon resulting from the collateral circulation which develops in the late stages of the ischemic stroke.