Structural alterations in Spinocerebellar Ataxia Type 3: A 3T baseline and longitudinal MRI study of cerebellar peduncles and cerebral pathways

Motivation: The first gene-silencing trials for Spinocerebellar Ataxia Type-3 (SCA3) highlights the need for non-invasive biomarkers. Goal(s): We aim to evaluate white matter (WM) tract integrity, identify early-alterations before clinical onset (preSCA3) and track disease progression over time. Approach: Analyze fractional anisotropy (FA) and mean diffusivity (MD) in WM tracts of healthy controls, preSCA3, and SCA3 patients at cross-sectional and longitudinal visits by employing a global and along-tract analysis. Results: While longitudinal analysis did not show relevant changes, alterations in preSCA3 in FA and MD were observed in all cerebellar peduncles and in the dentato-rubro-thalamo-cortical-tract, indicating their potential as promising stratification-biomarkers before clinical onset. Impact: This study offers a promising approach to differentiate early-stage SCA3 before clinical onset from healthy subjects, addressing clinical scale limitations. It underscores the potential of imaging biomarkers and the necessity for further research on disease progression modeling.