Characterizing white matter hyperintensities in myotonic dystrophy type 1 through DWI-derived metrics

Motivation: Myotonic dystrophy type 1 (DM1) is a variable multisystem disease, marked by widespread white matter hyperintensities (WMHs). Goal(s): Characterize periventricular WMHs (PWMHs) and deep WMHs (DWMHs) using Intra-Voxel Incoherent Motion (IVIM), and assess their impact on the cognitive domain. Approach: Examine the gradients of IVIM-derived metrics by distance and tissue type and correlate WMH features with clinical scores. Results: PWMHs show a diffusion gradient in tissue diffusivity with distance from the ventricles, supporting the idea of ventricular water infiltration, while DWMHs have stable diffusion values. Furthermore, DWMH volumes correlate with lower cognitive scores. Impact: There's no consensus on classifying WMH as PWMH or DWMH; common definitions rely on proximity to ventricles. IVIM-derived metrics may clarify lesions heterogeneity. Their distinction could be critical in understanding WMH link to cognitive decline in DM1 disease.