Regional Cerebral Blood Flow in Man: Establishment of “Normal” Control Values and Identification of the Abnormalities which Occur in “Stroke” Patients

Abstract

The human cerebral hemisphere consists of two very distinct types of tissue, grey matter, and white matter, which are perfused with blood at markedly different rates. To collect good regional data regarding blood flow in different parts of the cerebral hemisphere, it is necessary to use multiple detectors that are specifically designed to minimize the amount of overlap among adjacent detector fields. Grey matter perfusion is not homogeneous throughout the normal hemisphere in conscious patients or in patients anaesthetized by nitrous oxide and oxygen supplemented by neuroleptanalgesia (droperidol and phenoperidine). Grey matter perfusion is relatively homogeneous throughout the normal cerebral hemisphere in patients anaesthetised by the same technique, but studied during conditions of arterial hypocapnia. White matter perfusion is not homogeneous throughout the normal cerebral hemisphere. The ratio of the weight of perfused grey matter to perfused white matter is by no means constant throughout the hemisphere. The relative weight of grey matter is high in the insular region, low over the corpus callosum and corona radiata, and intermediate or high over the convexity of the hemisphere. Evidence is accumulating to confirm that two-compartmental analysis of regional 133 Xenon clearance curves provides a valid and detailed picture of the state of disordered perfusion that occurs in patients who have suffered various types of stroke.