Abstract
Abstract
Knee osteoarthritis is a serious disease in an aging society, and as there is currently no fundamental treatment, early diagnosis is extremely important. Cartilage is often modeled as a poroelastic body with a deformable solid matrix saturated with fluid or water, and its water retention capacity is assessed by the changes in the fluid content within the poroelastic body over time. Therefore, in this study, we focused on Poisson’s ratio as an evaluation index for fluid content. A speed-of-sound measurement method using the subchondral bone as a reflector is proposed, and Poisson’s ratio is calculated by combining the speed of sound measured using the aforementioned method with the shear wave speed measured using the time-of-flight method. As a preliminary cartilage evaluation study, we attempted to estimate the Poisson’s ratio of a cartilage phantom. As a result, the fluid content and Poisson’s ratio of the phantom showed a high correlation.