Cerebral Circulation Studies Using Inhaled 133-Xenon and the Gamma Camera

Inhaled 133-xenon was utilized in conjunction with the Anger gamma scintillation camera to evaluate cerebral circulation in 20 asymptomatic control subjects and in 41 patients with clinical cerebrovascular disease. Sequental cerebral scintipholos thus obtained revealed focal areas of decreased activity in 2 of 19 control subjects and in 15 of 38 patients. A computerized curve-fitting technique was used to calculate an index of cerebral blood flow ("K") by means of the 133-xenon clearance curves obtained from each half of the head. Shorter periods of 133-xenon inhalation resulted in more rapid rates of clearance. In patients with clinical cerebrovascular disease, cerebral clearance rates tended to be lower and to show more variation between the two sides of the head than in asymptomatic subjects.