HAI Book 2025 - Flipbook - Page 256
Parker, Dana
Mapping spatial white matter integrity linked to tau accumulation: Insights
from tractometry with multi-shell diffusion imaging
Dana Parker1, Jenna Adams1, Liv Mcmillan1, Michael Yassa1
1
University of California Irvine, Irvine, CA, US
Introduction: Tau pathology has the potential to disrupt white matter (WM) integrity. Previous work has shown
global disruption to these tracks. However, the specific spatial locations along the impacted tracts has yet to be
investigated in depth. Tractometry utilizes tractography to quantify WM integrity by placing equidistant nodes
along the length of white matter bundles. We assessed WM integrity along the spatial extent of medial temporal
lobe (MTL) tracts and investigated if tau pathology or cognitive impairment is associated with spatially-specific
patterns of WM integrity.
Methods: 159 older adults from ADNI3 (101 cognitively normal and 58 cognitively impaired (MCI/AD) participants)
received tau-PET (FTP) and multishell dMRI. Fractional anisotropy was calculated for each unilateral tract
(uncinate fasciculus [UF], inferior longitudinal fasciculus [ILF], inferior fronto-occipital fasciculus [IFOF]) along
100 equidistant nodes using pyAFQ. Tau-PET composite SUVRs within entorhinal cortex and amygdala (MTL tau)
and meta-temporal regions were extracted. A mixed effects model was performed to test for both main effects of
tau and diagnosis on WM integrity, and interactions between these factors by node, which indicate spatially
specific effects.
Results: When analyzing spatial WM integrity with tractometry, all tracts showed significant three-way
interactions between tau, diagnosis, and node location (ps
