CEREBRAL-CIRCULATION AND OXYGEN-METABOLISM IN CHILDHOOD MOYAMOYA DISEASE - A PERIOPERATIVE POSITRON EMISSION TOMOGRAPHY STUDY

Thirteen children with moyamoya disease who had no apparent cerebral i nfarction or hemorrhage were examined pre- and postoperatively by mean s of positron emission tomography (PET) to investigate the underlying cerebral circulation and metabolism and the effect of bypass surgery. The preoperative regional cerebral blood now (rCBF) and mean transit t ime were significantly decreased and increased, respectively, in the c erebral cortex of these patients compared to control values. The regio nal cerebral blood volume (rCBV) and the regional oxygen extraction fr action (rOEF) had significantly increased to compensate for the reduce d rCBF and perfusion pressure and also to maintain the regional cerebr al metabolic rate of oxygen (r CMRO(2)). In the basal ganglia, rCBV el evation was more prominent than that in the cerebral cortex, although changes in rCBF, rOEF, and rCMRO(2) were relatively minor. Postoperati ve improvements were observed predominantly near the cortex where bypa ss surgery had been performed and in the basal ganglia. Direct and com bined indirect bypass procedures improved cerebral circulation more ef fectively than single indirect bypass surgery. Although the angiograph ic findings were not always compatible with the clinical results, the postoperative improvements on PET scans correlated with the disappeara nce of transient ischemic attacks. In addition to the clinical courses and angiographic findings, PET analysis was indispensable in evaluati ng the cerebral circulation and metabolism in childhood moyamoya disea se.