Diffusion tensor imaging in mild cognitive impairment in community‐dwelling older adults in Taiwan

Abstract

AbstractBackgroundMost structural magnetic resonance imaging studies of Alzheimer’s disease and mild cognitive impairment (MCI) have focused on volumes of gray matter structures in the medial temporal lobe. This study aims to investigate white matter microstructures using diffusion tensor imaging (DTI) in MCI and different types of MCI in a community‐based cohort of older adults in Taiwan.MethodThe DTIs of 372 older adults at baseline from a community‐based prospective cohort study, the Epidemiology of Mild Cognitive Impairment in Taiwan (EMCIT) were used. Among them, 74 were ascertained as MCIs including 53 amnestic MCIs and 21 non‐amnestic MCIs. Tract‐based spatial statistics (TBSS) were used to compare voxelwise fractional anisotrophy (FA) differences between MCI, amnestic (aMCI), non‐amnestic MCI (naMCI) and cognitively normal (CN) older adults.ResultMean age of participants was 70.7± 5.3 years. Older adults with MCI were older, have lower education and higher prevalence of diabetes and depression. The pattern of white matter integrity disruption tends to follow an anterior to posterior gradient with greater damage noted in posterior regions in MCI (Fig. 1). On further analysis, participants with aMCI showed disrupted integrity in multiple white matter tracts across the whole‐brain when compared with CNs (Fig. 2) whereas only few white matter regions with diffusion changes were found in aMCI as compared to CNs and with less significance.ConclusionThese findings indicate that the degeneration extensively exists in white matter tracts in MCI, especially naMCI. The results are consistent with the view that MCI is not a uniform disease entity and presents heterogeneity in the structural brain changes.