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P4‐580: GLOBAL WHITE MATTER FIBRE DEGENERATION AFTER ISCHAEMIC STROKE
Author(s) -
Egorova Natalia,
Dhollander Thijs,
Brodtmann Amy
Publication year - 2019
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2019.08.128
Subject(s) - white matter , stroke (engine) , fasciculus , lesion , medicine , degeneration (medical) , superior longitudinal fasciculus , corticospinal tract , pathology , neuroscience , anatomy , psychology , magnetic resonance imaging , radiology , diffusion mri , fractional anisotropy , physics , thermodynamics
synaptic spines, dendrites, and axons. Recent advances in multishell diffusion weighted MRI provide a new approach for measuring these microscopic features in vivo. In this study, we used neurite orientation dispersion and density imaging (NODDI) to identify regional cortical and subcortical (gray and white matter) microstructural alterations that co-occur in conjunction with AD pathology within the AT(N) framework. Methods: 191 individuals from the Wisconsin Registry for Alzheimer’s Prevention study and Alzheimer’s Disease Research Center underwent lumbar puncture for CSF collection and multi-shell diffusion-weighted MRI (9 x b 1⁄4 500 s/mm, 18 x b 1⁄4 800 s/mm, and 36 x b 1⁄4 2000 s/mm; 2mmisotropic voxel resolution) and NODDI modeling. Cutoff values for CSF biomarker positivity that were previously developed using receiver operating characteristic curve analysis were used to classify groups by Ab42status, Ab42/Ab40(A), and phosphorylatedtau (T) pathology. Group differences [biomarker negative (A-T-) vs. biomarker positive (A+T+)] on mean orientation dispersion index (ODI) and neurite density (NDI) were tested using ANCOVA, controlling for age and sex, and applying FDR correction. Gray matter regions were defined by the Harvard-Oxford atlas; white matter regions were defined by the JHU atlas. Results: Demographics are shown in Table 1. After FDR correction, there were significant group differences in ODI and NDI in both gray and white matter regions. The A+T+ group showed substantially lower NDI compared to A-T(Table 2). Similarly, the A+T+ group showed lower ODI compared to A-Tin similar regions as the observed NDI differences, but with additional differences in gray matter cortices (Table 2, Figures 1,2) and fewer differences in white matter regions (Table 2, Figures 1,2).Conclusions: The present findings provide in vivoneuroimaging evidence of substantial loss of neurite density and complexity within the gray and white matter of participants with A+/T+ CSF. Future work will determine the extent to which the observed loss of neurite density and complexity inform upon the development of the clinical Alzheimer’s syndrome.