Quantitative ultrasound using backscatter analysis in Duchenne and Becker muscular dystrophy.

Evaluation of ultrasound images of muscle with calibrated muscle backscatter (cMB) provides reproducible quantitative measurements of muscle pathology. Increased cMB is associated with greater muscle pathology. We used cMB to evaluate the severity of muscle pathology in 55 patients with Duchenne and Becker Muscular Dystrophy (D/BMD) compared to 77 controls. cMB was also compared to measurements of strength and function. cMB in DMD and BMD increased linearly with age and was higher than in controls when groups are compared. cMB increased twice as fast with age in DMD than in BMD. In DMD, cMB was higher with reduced function and strength. Ultrasound measurement of muscle pathology using cMB is a sensitive and objective quantitative technique for determining the severity of muscle pathology in dystrophinopathies. Longitudinal studies are required to determine the sensitivity of this measure to changes in pathology over time.