Regional cerebral blood flow (rCBF) and cerebral vasoreactivity in patients with retinal ischaemic symptoms.

Regional cerebral blood flow (rCBF) and cerebral vasoreactivity were assessed in 28 consecutive patients who presented with retinal ischaemic symptoms, without clinical or cerebral CT evidence of cerebral ischaemia. rCBF was measured using xenon-133 inhalation and single photon emission computed tomography before and 20 minutes after the intravenous administration of 1 g acetazolamide. The findings suggest that patients with retinal ischaemic symptoms alone due to carotid atherosclerosis often have a carotid lesion which is of haemodynamic significance with regard to cerebral perfusion and vasoreactivity. Furthermore, localized areas with reduced cerebral perfusion may also be present in some patients, without evidence of precerebral carotid occlusive disease.