A simplified method of xenon-enhanced CT for regional cerebral blood flow (rCBF) measurement with reference to clinical experiences.

We introduced a simplified method of xenon-enhanced CT (SXe-CT) for obtaining the topographic regional cerebral blood flow (rCBF) map. In the SXe-CT, we used the method of brief (three to four minutes) inhalation of 40% xenon. To shorten the period of xenon inhalation, we substituted a predetermined brain-blood partition coefficient (L) in the entire brain for the directly estimated L to calculate the rCBF value. Because of its non-invasiveness and simplicity, the SXe-CT can be applied to the patients with diseases in the central nervous system (CNS) without any difficulties. During the past three years, we performed the SXe-CT on 150 occasions in 100 subjects, including those with moyamoya disease, other ischemic cerebrovascular diseases, arteriovenous malformations and normal pressure hydrocephalus. In this paper, the rCBF values of seven normal healthy adults with a mean age of 24 years are reported and the flow maps of some cases of CNS diseases are presented. The normal mean value of the hemispheres was 53, those of the gray matter were in the range of 38 to 72, those of the white matter were in the range of 26 to 35 and those of the basal ganglia and thalamus were 55 to 88 (values are given in ml/100 g/min). The SXe-CT has potential advantages in obtaining clinically useful rCBF measurements.