Effects of soft-tissue layer on shear wave velocity measurements in cortical bone tubes

Bone loss and deterioration caused by bone diseases, such us Osteoporosis can be effectively assessed by quantitative ultrasound techniques. Considering the elongated and curved nature of most of the human bones and, its complex structure surrounded by biological tissues, this study proposes the application of an ultrasound axial transmission technique to investigate the impact of bone curvature and the surrounding soft-tissue on the shear wave velocity measurement of bone tube samples. Measurements were validated by 3D elastic-FDTD simulations of bone tube models. Shear wave observations were analyzed in time and frequency domains. In previous measurements on plate samples (thickness: 1-2 mm), shear waves were observed at large incident angles. Similarly, it was found that shear velocity measurements of tube samples were not affected despite the bone curvature and the mimicking soft-tissue layer added. Present results suggested the possibility of implementing shear wave measurements for in vivo bone evaluation. (C) 2020 The Japan Society of Applied Physics