Attenuation of ultrasound in skeletal muscle.

Ultrasonic attenuation in fresh and 5% formalin fixed beef skeletal muscle has been measured, as a continuous function of frequency, in the range 1-8 MHz, for muscle fibre orientations both parallel and normal to the direction of propagation. Good agreement was found in all cases between two independent sets of measurements employing transmission and reflection techniques respectively. The data are consistent with a power law dependence of attenuation coefficient on frequency, with an exponent that is not significantly different from unity. For propagation normal to the fibres attenuation values are found as 1.1 +/- 0.15 and 1.6 +/- 0.15 dB cm-1 MHz-1 for fresh and fixed tissue respectively, the corresponding values for parallel propagation being 2.9 +/- 0.23 and 4.1 +/- 0.25 dB cm-1 MHz-1.