Abstract
Abstract BACKGROUND Associations between longitudinal changes of plasma biomarkers and cerebral magnetic resonance (MR)‐derived measurements in Alzheimer's disease (AD) remain unclear. METHODS In a study population ( n = 127) of healthy older adults and patients within the AD continuum, we examined associations between longitudinal plasma amyloid beta 42/40 ratio, tau phosphorylated at threonine 181 (p‐tau181), glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL), and 7T structural and functional MR imaging and spectroscopy using linear mixed models. RESULTS Increases in both p‐tau181 and GFAP showed the strongest associations to 7T MR‐derived measurements, particularly with decreasing parietal cortical thickness, decreasing connectivity of the salience network, and increasing neuroinflammation as determined by MR spectroscopy (MRS) myo‐inositol. DISCUSSION Both plasma p‐tau181 and GFAP appear to reflect disease progression, as indicated by 7T MR‐derived brain changes which are not limited to areas known to be affected by tau pathology and neuroinflammation measured by MRS myo‐inositol, respectively. Highlights This study leverages high‐resolution 7T magnetic resonance (MR) imaging and MR spectroscopy (MRS) for Alzheimer's disease (AD) plasma biomarker insights. Tau phosphorylated at threonine 181 (p‐tau181) and glial fibrillary acidic protein (GFAP) showed the largest changes over time, particularly in the AD group. p‐tau181 and GFAP are robust in reflecting 7T MR‐based changes in AD. The strongest associations were for frontal/parietal MR changes and MRS neuroinflammation.