Diffusion tensor imaging (mDTI) in myotonic dystrophy type 1 and type 2

<p>Background: Myotonic dystrophies type 1 and type 2 are hereditary myopathies characterized by dystrophic muscle degeneration of varying degrees. Differences in muscle diffusion between the two diseases have not yet been evaluated.</p><p>Objective: To evaluate the ability of muscle diffusion tensor imaging (mDTI) and Dixon fat quantification to distinguish between myotonic dystrophy (DM) type 1 and type 2 and to determine whether the two diseases exhibit distinct patterns of muscle involvement.</p><p>Methods: We evaluated 6 thigh and 7 calf muscles (from both legs) of 10 patients with DM type 1, 13 with DM type 2, and 28 healthy controls (HC) using diffusion tensor imaging, T1-weighted, and mDixon quant sequences on a 3T MRI scanner. The quantitative mDTI parameters—axial diffusivity (λ1), mean diffusivity (MD), radial diffusivity (RD), and fractional anisotropy (FA)—as well as fat fraction were analyzed. The CTG triplet repeat length of DM 1 patients was correlated with diffusion metrics and fat fraction.</p><p>Results: mDTI revealed significant differences between DM 1 and DM 2 patients compared to healthy controls in diffusion parameters of the thigh (all p < 0.001) except for FA (p = 0.0521 / 0.8337). In the calf muscles, mDTI revealed significant differences between Type 1 and Type 2 DM patients (all p < 0.0001) as well as between Type 1 DM patients and controls (all p = 0.0001). Thigh muscles had a significantly higher fat fraction in both groups compared to controls (p < 0.05). There was no correlation between CTG triplet length and mDTI values or fat fraction.</p><p>Discussion: mDTI reveals specific changes in diffusion parameters and fat fraction in the muscles of DM 1 and DM 2 patients. Thus, the quantitative MRI methods presented in this study provide a powerful tool for the differential diagnosis and follow-up of DM 1 and DM 2; however, the data must be validated in larger studies.</p><p>Keywords: Myotonic dystrophy</p>

DOI 10.1016/j.nmd.2022.07.368

WoSID 000873062200361

ORCID Source bibliographie.ub.rub.de/work/368315