Accumulation pattern of ischemic brain lesions with 18FDG and 13NH3

Positron emission computed tomography with Positologica-I was performed to 40-year-old man with multiple cerebral infarctions using 18F-fluorodeoxyglucose (18FDG) and 13N-ammonia (13NH3) as indicators of local glucose utilization and relative perfusion, respectively. In the old infarcted focus about 2 months after the first onset, all images of 18FDG, 13NH3 and X-ray CT (XCT) were shown as a complete defect with clear margins. Watershed area between anterior cerebral artery and middle cerebral artery had a severe decreased uptake with both of 18FDG and 13NH3 about one month after the second onset. Although there is no abnormal changes of the posterior cerebral circulation in the ipsilateral hemisphere, thalamic uptake of 18FDG was decreased and that of 13NH3 was normal on the ipsilateral hemisphere. The lesions increased with 13N activity appeared positive contrast enhancement by XCT, though 18F activity was normal or slightly decreased in the same lesions. From these preliminary results, positron computed tomography following injection of 18FDG and 13NH3 should aid in estimating the condition of altered brain about glucose utilization and perfusion after stroke. (author)