Measurement of Stress-Strain Properties of Tendon with Ultrasound Parameters

Quantitative ultrasound (QUS) measurements have been proposed for quantitative evaluation of bone tissue noninvasively. It also demonstrated to have the potential to evaluate the properties of tendon. Stress strain properties of tendon are important information for many clinical applications, such as monitoring the recovering progression of surgery or overloading of tendon. Therefore, in this study we designed a system combining QUS technique and stress-strain measurement for tendon by studying the correlation between the stress strain properties and QUS parameters. The proposed system consists of three major devices to measure 1) stress, 2) QUS parameters, and 3) cross-sectional areas of tendons. A laser displacement sensor mounted on a rotary was designed to measure the cross-sectional area. Achilles tendons used in the experiments were obtained from 10 porcine specimens. The results show that the cross-sectional area of tendon decreases with increased loading, which has high correlation (

R

2

= 0.73) with the thickness evaluated by ultrasonic technique. In addition, the obtained QUS parameters show that both ultrasonic attenuation and speed of sound (SOS) decrease along with increased loading. In conclusion, thickness evaluated by ultrasonic technique is useful for calculating QUS parameters, and for analyzing non-uniform soft tissues. This study indicated that the attenuation and SOS are potential candidate parameters for evaluating the properties of tendon noninvasively.