title: Numerical and experimental study on the wave attenuation in bone--FDTD simulation of ultrasound propagation in cancellous bone.
abstract: In cancellous bone, longitudinal waves often separate into fast and slow waves depending on the alignment of bone trabeculae in the propagation path. This interesting phenomenon becomes an effective tool for the diagnosis of osteoporosis because wave propagation behavior depends on the bone structure. Since the fast wave mainly propagates in trabeculae, this wave is considered to reflect the structure of trabeculae. For a new diagnosis method using the information of this fast wave, therefore, it is necessary to understand the generation mechanism and propagation behavior precisely. In this study, the generation process of fast wave was examined by numerical simulations using elastic finite-difference time-domain (FDTD) method and experimental measurements. As simulation models, three-dimensional X-ray computer tomography (CT) data of actual bone samples were used. Simulation and experimental results showed that the attenuation of fast wave was always higher in the early state of propagation, and they gradually decreased as the wave propagated in bone. This phenomenon is supposed to come from the complicated propagating paths of fast waves in cancellous bone.
authors.affiliation: Department of Otorhinolaryngology, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522, Japan. naramed-u@nagatani.ne.jp
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Nagatani
authors.forename: Katsunori
authors.initials: K
authors.lastname: Mizuno
authors.forename: Takashi
authors.initials: T
authors.lastname: Saeki
authors.forename: Mami
authors.initials: M
authors.lastname: Matsukawa
authors.forename: Takefumi
authors.initials: T
authors.lastname: Sakaguchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hosoi
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000000981:diagnostic imaging* / Q000502:physiology; D002417:Cattle; D003198:Computer Simulation; D054459:Elasticity Imaging Techniques / Q000379:methods*; D020342:Finite Element Analysis; D006801:Humans; D008954:Models, Biological; D010024:Osteoporosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016012:Poisson Distribution; D012815:Signal Processing, Computer-Assisted