Initial research on the damaged characteristics of cerebral glucose metabolism and cerebral blood flow in patients with severe cerebral artery stenosis

Objective To investigate the damaged characteristics of cerebral glucose metabolism （CGM）and cerebral blood flow （CBF）in ischemic cerebrovascular disease （ICVD）patients with severe cerebral artery stenosis or occlusion. Methods Thirty-three cases of ICVD patients were examined by 18F-FDG PET and 13N-Ammonia PET, obtaining the same stages of cerebral blood perfusion and glucose metabolism image. According to the semi-quantitative analysis, the rate of reductions in CGM and CBF, and the ratio of CGM/CBF were figured out. Results ①There were 121 foci in total, positive rate of 18F-FDG imaging was 91.7%, and 13N-Ammonia imaging was 78.5%. ②ICVD foci were mostly characterized with multifocal and asymmetric distribution.③Based on visual analysis to the relationship of FDG images and Ammonia images, 121 foci were divided into two types： matched damage in 66 foci （54.5%, type I）and mismatched damage in 55 foci （45.5%, type II-type V）.④Based on semi-quantitative study to matched and mismatched group, the ratio of CGM/CBF with 1.1-1.3 may be considered as the parameter in evalu-ation.⑤Based on the rate of reductions in CGM and CBF, 66 matched foci were divided into mild （27 fo-ci, 40.9%）, moderate（15 foci, 22.7%）and severe（24 foci, 36.4%） damage group.⑥4 cases with unilat-eral foci appeared crossed cerebellar diaschisis. Conclusions The matched relationship of CGM and CBF was markedly damaged in IVCD patients with sever cerebral artery stenosis but different degrees of injury on metabolism and blood flow were also found. The application of combined imaging with 18F-FDG and 13N-Ammonia brain PET is able to greatly improve ICVD diagnosis and management. Key words: Positron-emission tomography; Cerebral glucose metabolism; Cerebral blood perfusion; Ischemic cerebrovascular disease