Clinical studies of biceps anisotropy, relaxation and nonlinearity with a medical device for ultrasonic imaging

We applied a commercial ultrasonic clinical diagnostic system for studies of human biceps. The investigated area was visualized in B-mode at a frequency of 8 MHz. We selected 1 cm and 2.5 cm depths for shear wave excitation. On these depths, the focused ultrasonic wave caused the acoustical radiation force. Due to nonlinear mechanism of excitation, a shear wave arose. The results we have obtained show that the biceps have the shear moduli of the order of 10 kPa. The loaded biceps demonstrated the nonlinear behavior better pronounced for the volunteer with smaller body mass index (BMI). As the load on the biceps increases, the shear modulus measured along the muscle fibers grows. The observed growth was stronger for the shear modulus of the short head. The shear modulus, measured in the direction across the fibers of the biceps, does not depend on the magnitude of the applied load and remains at the unloaded value. In 1 minute after load is removed the biceps tend to relax and its shear moduli turn their initial values.We applied a commercial ultrasonic clinical diagnostic system for studies of human biceps. The investigated area was visualized in B-mode at a frequency of 8 MHz. We selected 1 cm and 2.5 cm depths for shear wave excitation. On these depths, the focused ultrasonic wave caused the acoustical radiation force. Due to nonlinear mechanism of excitation, a shear wave arose. The results we have obtained show that the biceps have the shear moduli of the order of 10 kPa. The loaded biceps demonstrated the nonlinear behavior better pronounced for the volunteer with smaller body mass index (BMI). As the load on the biceps increases, the shear modulus measured along the muscle fibers grows. The observed growth was stronger for the shear modulus of the short head. The shear modulus, measured in the direction across the fibers of the biceps, does not depend on the magnitude of the applied load and remains at the unloaded value. In 1 minute after load is removed the biceps tend to relax and its shear moduli turn their i...