Fixel-Based Analysis Effectively Identifies White Matter Tract Degeneration in Huntington's Disease.

Sher Li Oh,Jur-Shan Cheng,Yi-Ming Wu,Yao-Liang Chen,Chiung-Mei Chen,Jiun-Jie Wang,Yih-Ru Wu,Yu-Chun Lin,Maria Valdes Hernandez,Chih-Chien Tsai

doi:10.3389/fnins.2021.711651

Abstract

Microstructure damage in white matter might be linked to regional and global atrophy in Huntington’s Disease (HD). We hypothesize that degeneration of subcortical regions, including the basal ganglia, is associated with damage of white matter tracts linking these affected regions. We aim to use fixel-based analysis to identify microstructural changes in the white matter tracts. To further assess the associated gray matter damage, diffusion tensor-derived indices were measured from regions of interest located in the basal ganglia. Diffusion weighted images were acquired from 12 patients with HD and 12 healthy unrelated controls using a 3 Tesla scanner. Reductions in fixel-derived metrics occurs in major white matter tracts, noticeably in corpus callosum, internal capsule, and the corticospinal tract, which were closely co-localized with the regions of increased diffusivity in basal ganglia. These changes in diffusion can be attributed to potential axonal degeneration. Fixel-based analysis is effective in studying white matter tractography and fiber changes in HD.

Highlights

Huntington’s Disease (HD) is an autosomal dominant genetic disease that results in progressive neurodegeneration
Reduced fiber density and cross-section (FDC) and fiber bundle cross-section (FC) were observed in the corticospinal tract (Figure 3)
Our study found a reduction in fixel-derived metrics in the corpus callosum of patients with HD compared to healthy control participants

Summary

Introduction

Huntington’s Disease (HD) is an autosomal dominant genetic disease that results in progressive neurodegeneration. Large-scale longitudinal MRI cohort studies focused mainly on identifying biomarkers of HD that can indicate disease progression before and after clinical diagnosis throughout different stages (Paulsen et al, 2008; Tabrizi et al, 2012; Domínguez D et al, 2013). Both PET and functional MRI have been used to evaluate brain functions during HD progression (Paulsen, 2009)

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