Preliminary study on the speed-of-sound measurement of cartilage tissue based on a two-layer model

This is the authors' abstract. We don't add key points for this paper.

Knee osteoarthritis is a serious disease in an aging society, and early diagnosis is crucial because no fundamental treatment currently exists. Cartilage is often modeled as a poroelastic body with a deformable solid matrix saturated with fluid or water, and its water retention capacity is evaluated by the change in fluid content in the poroelastic body over time. In this study, we focus on the speed of sound as an indicator of fluid content. Considering the actual structure including soft and cartilage tissues, we propose a method for measuring the speed of sound in cartilage tissue using the cartilage surface and subchondral bone surface as reflectors. The effectiveness of the proposed method was demonstrated by performing simulations and phantom experiments, and the measured values of the speed of sound coincided well with the true values in both the simulations and phantom experiments.