Regional cerebral blood flow measurement in humans by xenon-133 clearance.

Almost 30 years have passed since the first measurement of regional cerebral blood flow in humans by 133Xe clearance. A review of the methodology is presented for the two-dimensional intracarotid method and the related inhalation and IV injection techniques. Emphasis is placed on the mathematical models employed and the blood flow indices derived from them. Similarities and differences between methods are described, and the contribution of each to clinical research is summarized.