PHOTOREACTIVE FLOW CHANGES IN THE POSTERIOR CEREBRAL-ARTERY IN CONTROL SUBJECTS AND PATIENTS WITH OCCIPITAL LOBE INFARCTION

Background and Purpose Photoreactive flow changes of the posterior cerebral artery (PCA) in control subjects and patients with unilateral occipital lobe infarction were investigated to study the hypothesis that occipital lobe infarction of varying extent leads to a reduced visually activated flow increase in the ipsilateral PCA. Methods Maximum mean flow velocity (MFV) of the PCA was investigated by transcranial Doppler sonography after photic stimulation of the retina. Results In 25 control subjects MFV was increased by 30.6+/-9.7%. In 13 patients with unilateral occipital lobe infarction the ipsilateral MFV increase was significantly lower than in control subjects. Nine patients with homonymous hemianopsia showed an ipsilateral MFV increase of 3.41+/-4.1% (P<.001) and four patients with incomplete occipital lobe infarction and homonymous quadrantanopsia had an MFV increase of 16.0+/-12.8% (P<.05). Conclusions We conclude that photoreactive flow changes of the PCA represent a noninvasive and reliable measure of functional impairment due to occipital infarction.