title: Simulation study of axial ultrasonic wave propagation in heterogeneous bovine cortical bone.
abstract: The effect of the heterogeneity of the long cortical bone is an important factor when applying the axial transmission technique. In this study, the axial longitudinal wave velocity distributions in specimens from the mid-shaft of a bovine femur were measured, in the MHz range. Bilinear interpolation and the piecewise cubic Hermite interpolating polynomial method were used to construct three-dimensional (3D) axial velocity models with a resolution of 40 μm. By assuming the uniaxial anisotropy of the bone and using the results of previous experimental studies [Yamato, Matsukawa, Yanagitani, Yamazaki, Mizukawa, and Nagano (2008b). Calcified Tissue Int. 82, 162-169; Nakatsuji, Yamamoto, Suga, Yanagitani, Matsukawa, Yamazaki, and Matsuyama (2011). Jpn. J. Appl. Phys. 50, 07HF18], the distributions of all elastic moduli were estimated to obtain a 3D heterogeneous bone model and a uniform model. In the heterogeneous model, moduli at the surface were smaller than those inside the model. The elastic finite-difference time-domain method was used to simulate axial ultrasonic wave propagation in these models. In the heterogeneous model, the wavefront of the first arriving signal (FAS) was dependent on the heterogeneity, and the FAS velocity depended on the measured position. These phenomena were not observed in the uniform model.
authors.affiliation: Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe 610-0321, Japan.
authors.forename: Toshiho
authors.initials: T
authors.lastname: Hata
authors.affiliation: Department of Electronics, Kobe City College of Technology, Kobe 651-2194, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Nagatani
authors.affiliation: Faculty of Science and Engineering, Doshisha University, Kyotanabe 610-0321, Japan.
authors.forename: Koki
authors.initials: K
authors.lastname: Takano
authors.affiliation: Faculty of Science and Engineering, Doshisha University, Kyotanabe 610-0321, Japan.
authors.forename: Mami
authors.initials: M
authors.lastname: Matsukawa
mesh_terms: D000818:Animals; D016880:Anisotropy; D001842:Bone and Bones; D002417:Cattle; D000071538:Cortical Bone; D004548:Elasticity; D000069453:Ultrasonic Waves