The microstructural changes of white matter pathways in children of patients with Alzheimer?s Disease through diffusion MRI data

SÁNCHEZ S. M.; DE PINO G.; BOCACCIO H.; CASTRO M. N.; DUARTE-ABRITTA B.; ABULAFIA C.; VIGO D.; VILLARREAL M.; GUINJOAN S. M.

Buenos Aires

Congreso; Frontiers in Bioscience 3; 2018

The earliest preliminary neuropathological anomalies characteristic of Alzheimer?s disease involve intracellular Tau accumulation ultimately affecting white matter tracts. The microstructure of these tracts can be assessed through metrics derived from methods developed to reconstruct pathways by connecting local white matter orientations obtained from diffusion MRI data. This approach enables researchers to trace whole fiber trajectories and link different grey matter regions. In scenarios where the usual diffusion metrics, such as fractional anisotropy (FA) or mean diffusivity (MD), are difficult to interpret or don?t show subtle anomalies, alternative metrics can be used to study fiber tract differences within a voxel: fiber density, fiber bundle cross-section and these two methods combined. These metrics are obtained through fiber based analysis (FBA). In this work, we tested the hypothesis that this analysis could reveal early anomalies in 3D-reconstructed fiber tracts and in white matter integrity in middle-aged, cognitively intact individuals (O-LOAD, n=25) who present a higher risk of developing late-onset Alzheimer?s disease (LOAD) by virtue of having at least one parent diagnosed when compared to normal individuals without family history of neurodegenerative disorders (CS, n=25). In addition, we hypothesized the microstructure of white matter tracts that link AD-relevant areas would be altered in O-LOAD due to fibers affected by hyperphosphorylated tau. Our findings suggest that metrics of specific white matter tracts derived from FBA were different in CS and O-LOAD, which is in line with numerous studies of Alzheimer?s disease with different techniques.