Improved method for noninvasive measurement of regional cerebral blood flow by 133Xenon inhalation. Part II: measurements in health and disease.

The current state of the art of noninvasive measurement of regional cerebral blood flow (rCBF) by inhalation of Xe gas is briefly reviewed. Apparatus is now available commercially so thatprintouts of rCBF values for gray and white matter flow of both cerebral hemispheres, and probably the brain stem and cerebellum, are available within 30 minutes after 1 minute inhalation of 5-6 mCi of the gas mixed in air. The printout is in the form of a brain map whichshows normal values. Normal values reported in volunteers are discussed and modifications of rCBF caused by normal physiological function such as sleep, attention, activation, speech, hearing, performance of tasks and the normal aging process are reviewed. Noninvasive rCBFmeasurements have some practical clinical and investigative applications in the evaluation of pathological states such as cerebrovascular disease, the dementias, migraine, epilepsy, narcolepsy, and head injuries. Despite certain technical limitations of the Xe inhalation method, which are described, rCBF measurements show promisefor future screening of populations at risk from cerebrovascular disease, early identification of stroke-prone individuals, evaluation of methods of prevention, as well as measurement of the effects of medical and surgical treatment.