لخّصلي

Previous studies of aging efects on fuorine-18-labeled fuorodeoxyglucose (18F-FDG) distribution have employed cross-sectional designs.The voxel-wise analysis revealed signifcant clusters in which 18F- FDG uptake was decreased between baseline and second scans (p<0.05, family-wise error corrected) in the anterior cingulate cortex (ACC), posterior cingulate cortex/precuneus (PCC/PC), and lateral parietal cortex (LPC).The results of longitudinal assessments suggested that 18F-FDG uptake in the ACC, PCC/PC, and LPC decreased with advancing age in cognitively normal elderly individuals, and those of the cross-sectional assessments suggested that the trajectories of age-associated 18F-FDG decreases difered between the ACC and PCC/PC.In particular, recent cross-sectional 18F-FDG PET studies have shown that the medial part of the prefrontal cortex, the anterior cingulate cortex (ACC), exhibits highly signifcant age-associated decreases in 18F-FDG uptake5,6,8,9,12.One major drawback of the above cross-sectional studies is that inter-individual variabilities in physiological and anatomical factors at certain ages, such as 18F-FDG distribution and brain structure, may afect the fndings of aging efects on 18F-FDG distribution.Fluorine-18-labeled fuorodeoxyglucose (18F-FDG) is a radioligand used in positron emission tomography (PET) to estimate regional glucose metabolism, which refects regional brain activity1 .As the numbers of elderly individuals in the world population and patients with senile dementia are increasing, understanding the efects of aging on brain activity is essential for comprehending the progress of senile dementia, such as Alzheimer's disease (AD), dementia with Lewy bodies, and frontotemporal dementia.Tese studies failed to observe signifcant efects of aging on 18F-FDG distribution in elderly individuals, likely due to smaller sample sizes and shorter follow-up periods14,15.We obtained two 18F-FDG positron emission tomography scans at two diferent time points from 107 cognitively normal elderly participants.

Previous studies of aging efects on fuorine-18-labeled fuorodeoxyglucose (18F-FDG) distribution have
employed cross-sectional designs. We examined aging efects on 18F-FDG distribution using both cross-
sectional and longitudinal assessments. We obtained two 18F-FDG positron emission tomography scans
at two diferent time points from 107 cognitively normal elderly participants. The participants’ mean
ages at baseline and second scans were 67.9 and 75.7, respectively. The follow-up period ranged from 4
to 11 years with a mean of 7.8 years. The voxel-wise analysis revealed signifcant clusters in which 18F-
FDG uptake was decreased between baseline and second scans (p