The Study On Regional Cerebral Metabolic Rate Of Glucose In Amnestic Mild Cognitive Impairment

Objective:This study aimed to early diagnose of Alzheimer's disease(AD) by studying the cerebral metabolic characteristics of amnestic mild cognitive impairment(aMCI) through 18F-fluorodeoxyglucose- hybrid positron emission tomography(18F-FDG-hPET).Methods:Through the basic clinical data collection, medical history review, physical examination and neurological examination, cognitive psychological assessment, laboratory examination and Magnetic Resonance Imaging (MRI) examination, the study enrolled 7 aMCI,8 mild AD and 5 healthy control (HC) for brain 18F-FDG metabolic imaging. Compare the 18F-FDG-hPET metabolic characteristics of the aMCI, mild AD and HC groups by using three methods of the visual analysis, region of interest(ROI) and statistical parameter mapping(SPM). Cluster analysis of the aMCI group based on the cerebral metabolic characteristics. Results:(1) From the visual, ROI and SPM analysis results, there was significant decreasing of radioactivity of temporal and parietal lobes in aMCI group. The AD group showed uneven cerebral distribution of 18F-FDG radioactivity, decreased significantly in the frontal, temporal and parietal lobes. Both AD and aMCI groups didn't show reduced FDG metabolism in occipital lobe. Further quantitative analysis indicated that, the regional cerebral metabolic rate of glucose (rCMRglc) of many parts of brain such as frontal lobe (left), temporal lobe, parietal lobe, cingulate gyrus, hippocampus and amygdala (left) decreased significantly in AD compared to aMCI(P<0.05-P<0.001). The rCMRglc of many parts of brain such as frontal lobe, temporal lobe, parietal lobe, cingulate gyrus and hippocampus decreased significantly in AD compared to HC (P< 0.05-P< 0.001). The rCMRglc of many parts of brain such as temporal lobe, orbital gyrus, caudate head (left), hippocampus (right), anterior cingulate (right) and medial globus pallidus (right) decreased significantly in aMCI compared to HC (P< 0.05-P< 0.001)(2) By cluster analysis based on the cerebral metabolic characteristics, the aMCI were clustered into cluster 1 and 2. The rCMRglc of bilateral parietal lobe, right posterior cingulate gyrus, right precuneus and right hippocampus were decreased without statistically significant in cluster 1 compared to cluster 2.Conclusion:(1) Those aMCI whose 18F-FDG metabolism decreased in temporal lobe, parietal lobe, cingulate gyrus and hippocampus are with higher risk in the progress to AD.(2) Cluster analysis can't predict the different outcomes of aMCI.