NON-INVASIVE ASSESSMENT OF MUSCLE STIFFNESS IN PATIENTS WITH DUCHENNE MUSCULAR DYSTROPHY

Introduction: Assessment of muscle mechanical properties may provide clinically valuable information for follow-up of patients with Duchenne muscular dystrophy (DMD) through the course of their disease. In this study we aimed to assess the effect of DMD on stiffness of relaxed muscles using elastography (supersonic shear imaging). Methods: Fourteen DMD patients and 13 control subjects were studied. Six muscles were measured at 2 muscle lengths (shortened and stretched): gastrocnemius medialis (GM); tibialis anterior (TA); vastus lateralis (VL); biceps brachii (BB); triceps brachii (TB); and abductor digiti minimi (ADM). Results: Stiffness was significantly higher in DMD patients compared with controls for all the muscles (main effect for population, P<0.033 in all cases), except for ADM. The effect size was small (d=0.33 for ADM at both muscle lengths) to large (d=0.86 for BB/stretched). Conclusions: Supersonic shear imaging is a sensitive non-invasive technique to assess the increase in muscle stiffness associated with DMD. Muscle Nerve 51: 284-286, 2015