A STUDY OF THE RELATIONSHIP BETWEEN MECHANICAL AND ULTRASONIC PROPERTIES OF DYSTROPHIC AND NORMAL SKELETAL-MUSCLE

A study has been made of the application of radio frequency (RF) ultra sound to the detection of muscular dystrophy by monitoring passively s tretched skeletal muscle. The tests included detection of integrated b ackscatter changes in response to both static loading, in which muscle samples were stretched and allowed to relax, and stress relaxation. I n both static and step strain loading conditions, the dystrophic muscl e was found to exhibit little change in backscatter power while normal muscle responded to loading with significant changes in integrated ba ckscatter. The backscatter response is compared with mechanical proper ties of the tissue (time constants and stress-strain constants). Both mechanical and ultrasonic time constants of relaxation are not signifi cantly different between normal and dystrophic tissue, but stress-stra in constants do differ. The difference in response of dystrophic and n ormal tissue appears to be due to a repression of motion of the consti tuent anatomy of dystrophic muscle which is responsible for the change of echogenicity with passive stretch.