Diffusion MRI relates to plasma Aβ42/40 in PET negative participants without dementia
Jesse C. DeSimone, Wei‐en Wang, David A. Loewenstein, Ranjan Duara, Glenn E. Smith, Karen N. McFarland, Melissa J. Armstrong, Darren M. Weber, Warren Barker, Stephen A. Coombes, David E. Vaillancourt- Psychiatry and Mental health
- Cellular and Molecular Neuroscience
- Geriatrics and Gerontology
- Neurology (clinical)
- Developmental Neuroscience
- Health Policy
- Epidemiology
Abstract
INTRODUCTION
Magnetic resonance imaging (MRI) biomarkers are needed for indexing early biological stages of Alzheimer's disease (AD), such as plasma amyloid‐β (Aβ42/40) positivity in Aβ positron emission tomography (PET) negative individuals.
METHODS
Diffusion free‐water (FW) MRI was acquired in individuals with normal cognition (NC) and mild cognitive impairment (MCI) with Aβ plasma‐/PET‐ (NC = 22, MCI = 60), plasma+/PET‐ (NC = 5, MCI = 20), and plasma+/PET+ (AD dementia = 21) biomarker status. Gray and white matter FW and fractional anisotropy (FAt) were compared cross‐sectionally and the relationships between imaging, plasma and PET biomarkers were assessed.
RESULTS
Plasma+/PET‐ demonstrated increased FW (24 regions) and decreased FAt (66 regions) compared to plasma‐/PET‐. FW (16 regions) and FAt (51 regions) were increased in plasma+/PET+ compared to plasma+/PET‐. Composite brain FW correlated with plasma Aβ42/40 and p‐tau181.
DISCUSSION
FW imaging changes distinguish plasma Aβ42/40 positive and negative groups, independent of group differences in cognitive status, Aβ PET status, and other plasma biomarkers (i.e., t‐tau, p‐tau181, glial fibrillary acidic protein, neurofilament light).
Highlights
Plasma Aβ42/40 positivity is associated with brain microstructure decline. Plasma+/PET‐ demonstrated increased FW in 24 total GM and WM regions. Plasma+/PET‐ demonstrated decreased FAt in 66 total GM and WM regions. Whole‐brain FW correlated with plasma Aβ42/40 and p‐tau181 measures. Plasma+/PET‐ demonstrated decreased cortical volume and thickness.