Cerebral blood flow measurement as an indicator of the haemodynamic severity of carotid artery disease in man.

The non-invasive xenon-133 inhalation technique was used to measure regional cerebral blood flow in 61 patients with cerebrovascular disease in whom carotid angiography had been performed before carotid endarterectomy or extracranial/intracranial arterial bypass were considered. Hemispheric cerebral blood flow (CBF) was significantly lower in patients with an ipsilateral internal carotid artery occlusion than in those with a patent vessel. CBF values were also influenced by disease of the contralateral carotid artery. The cerebrovascular response to hypercapnia was a more sensitive index of carotid disease; a significant reduction in CO2 responsiveness was found both with occlusion and stenosis of the ipsilateral internal carotid artery. These data suggest that CBF measurements may be clinically useful in selecting patients for angiography and surgery.