Correlation between Brain 18F-AV45 and 18F-FDG PET Distribution Characteristics and Cognitive Function in Patients with Mild and Moderate AD

Background: The purpose of this study is to investigate the characteristics of amyloid beta (Aβ) load and fluorodeoxyglucose (FDG) metabolism and analyze their correlation with cognitive impairment in the cerebral cortex of Alzheimer's disease (AD) patients using 18 F-florbetapir ( 18 F-AV45) and 18 F-FDG PET technology. Methods 27 patients with AD were enrolled. All AD patients underwent detailed clinical and imaging examinations of the nervous system, completed the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) tests, and finished 18F-AV45 and 18F-FDG PET scans. NeuroQ software was used to analyze PET images. Results 81.48% (22 out of 27) AD patients had significantly increased Aβ load and 96.30% (26 out of 27) had significantly reduced FDG metabolism. Moderate AD patients had more brain areas of reduced FDG metabolism with more severe reduction in some brain regions compared with mild AD patients, despite there was no differences of Aβ load between these patients. The range of reduced FDG metabolism was negatively correlated with the total scores of MMSE and MoCA, and the degree of FDG metabolism in some brain regions was positively correlated with the total score of MMSE and MoCA. Conclusion Brain 18 F-AV45 and 18 F-FDG imaging may be potential biomarkers of AD, and 18 F-FDG imaging is correlated with the degree of cognitive impairment in AD patients.