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DT-MRI with the random permeable barrier model shows larger, more heterogeneous muscle fibre diameters in Becker muscular dystrophy patients

Donnie Cameron^1,2, Jedrzej Burakiewicz¹, Nienke M. van de Velde³, Celine Baligand¹, Thom T.J. Veeger¹, Melissa T. Hooijmans⁴, Jan J.G.M. Verschuuren³, Erik H. Niks³, and Hermien Kan¹
¹C.J. Gorter Centre for High Field MRI, Department of Radiology, Leiden University Medical Centre, Leiden, Netherlands, ²Norwich Medical School, University of East Anglia, Norwich, United Kingdom, ³Department of Neurology, Leiden University Medical Centre, Leiden, Netherlands, ⁴Biomedical Engineering and Physics, Amsterdam University Medical Centre, Amsterdam, Netherlands

In Becker muscular dystrophy patients, DTI with the random permeable barrier model shows larger and more variable fibre diameters than in age-matched controls. Conventional DTI parameters show intramuscular differences and time-dependence but do not significantly differ between groups.

Fig. 1. Representative lower-leg Dixon images and STE-DTI parameter maps from a 59-year-old Becker muscular dystrophy (BMD) patient (a) and a 58-year-old healthy control (b). STE-DTI data were acquired with a diffusion time, Δ, of 330 ms, and mean, axial, and radial diffusivities are shown in units of μm²/s. The BMD patient shows severe fat replacement in the gastrocnemius medialis and lateralis, and peroneus longus and extensor digitorum longus muscles (fat fraction = 83, 77, 77, and 64%, respectively). This leads to signal voids in the comprehensively-fat-suppressed DTI data.

Fig. 4. Fibre diameter, a, and membrane permeability, κ, from the random permeable barrier model in Becker muscular dystrophy patients and controls. Boxplots (top) show a and κ over the soleus (SOL), medial gastroc. (GAM), lateral gastroc. (GAL), tibialis anterior (TAN), tibialis posterior (TPO), peroneus longus (PER), and extensor digitorum longus (EDL). Median values = thick lines, hinges = 25th and 75th percentiles, and dots = raw data. Maps (middle) show a and κ in a 59-year-old patient and 58-year-old control. Density plots (bottom) show a and κ distributions from maps above.