An MRI-based macro- and microstructural neuroimaging-wide association study of subsequent cognitive impairment

INTRODUCTION: This study longitudinally examined 154 magnetic resonance imaging (MRI) biomarkers in cognitively normal (CN) individuals to identify structural brain changes most strongly associated with subsequent cognitive impairment (SI). METHODS: We analyzed 509 Baltimore Longitudinal Study of Aging participants (age ≥ 50, CN at baseline) with longitudinal cognitive and 3T MRI (T1/T2-weighted scans and diffusion tensor imaging) data. MRI biomarker associations with SI status were analyzed, adjusting for confounders and stratifying by sex and amyloid beta (Aβ) status. RESULTS: Participants who developed SI over 4.6 years' follow-up showed greater longitudinal changes in white matter (WM) integrity, particularly in the corpus callosum, cingulum bundle, and inferior fronto-occipital fasciculus, compared to CN-stable. To a lesser degree, we also observed temporal thinning and atrophy linked to SI. These associations were amplified among males and amyloid-positive individuals. DISCUSSION: Longitudinal alterations in WM microstructural integrity were most strongly associated with future impairment, highlighting the importance of early WM changes in the development of MCI and dementia.