A PET study of discrimination of cerebral glucose metabolism in Alzheimer's disease and mild cognitive impairment

Imaging cerebral glucose metabolism with positron emission tomography (PET) has been widely used in studying Alzheimer's disease (AD) and mild cognitive impairment (MCI). In this study, we used fluoro-deoxyglucose (FDG) PET images to investigate reduced glucose metabolism in 90 AD subjects, 90 MCI subjects and 90 healthy elderly normal controls (NC). Compared to NC, the AD showed a significant hypometabolism in left and right middle temporal, left cingulate gyrus, medial frontal gyrus and left parahippocampal gyrus. Compared to NC, the MCI showed a significant hypometabolism in the right inferior temporal gyrus and right fusiform gyrus. Compared to MCIs, the AD also showed a significant hypometabolism in left and right middle temporal, left cingulate gyrus, left angular gyrus and right parahippocampal gyrus. This study demonstrates the different cerebral metabolic patterns of AD, MCI and controls. It also shows that glucose metabolism is a sensitive measure of change in cognition and functional ability in AD and MCI, and that might be valuable in predicting future cognitive decline.