Cerebral Vasomotor Responsiveness During 100% Oxygen Inhalation in Cerebral Ischemia

149 subjects, including normal healthy volunteers without risk factors (N=49, aged 25 to 86 years), asymptomatic subjects with risk factors for cerebral arteriosclerosis (N=38), and patients with hemispheric stroke and vertebrobasilar insufficiency (N=62).

100% oxygen inhalation (measured with the 133Xe inhalation method)

Comparison across patient groups (normal volunteers vs. asymptomatic subjects with risk factors vs. patients with hemispheric stroke and vertebrobasilar insufficiency)

Cerebral vasoconstrictor responsiveness (hemispheric gray matter flow [Fg] values)surrogate