Numerical and experimental study on the wave attenuation in bone – FDTD simulation of ultrasound propagation in cancellous bone

• Published in: Ultrasonics Vol. 48; no. 6; pp. 607 - 612
• Main Authors: Nagatani, Yoshiki, Mizuno, Katsunori, Saeki, Takashi, Matsukawa, Mami, Sakaguchi, Takefumi, Hosoi, Hiroshi
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2008; Elsevier
• Subjects: Acoustics; Animals; Biological and medical sciences; Bone and Bones - diagnostic imaging; Bone and Bones - physiology; Cancellous bone; Cattle; Computer Simulation; Elasticity Imaging Techniques - methods; Exact sciences and technology; Fast wave; Finite Element Analysis; Fundamental and applied biological sciences. Psychology; Fundamental areas of phenomenology (including applications); Humans; Investigative techniques, diagnostic techniques (general aspects); Medical sciences; Miscellaneous. Technology; Models, Biological; Osteoporosis - diagnostic imaging; Osteoporosis - physiopathology; Physics; Poisson Distribution; Signal Processing, Computer-Assisted; Skeleton and joints; Three-dimensional elastic FDTD method; Ultrasonic investigative techniques; Ultrasonics, quantum acoustics, and physical effects of sound; Vertebrates: osteoarticular system, musculoskeletal system; X-ray CT; Three-dimensional elastic FDTD method; X-ray CT; Cancellous bone; Fast wave; Human; X ray radiography; Diseases of the osteoarticular system; Wave damping; Longitudinal wave; Experimental study; Modeling; Computerized tomography; Osteoarticular system; Osteoporosis; Alignment; Time domain method; Diagnosis; Spongious bone; Finite difference method
• ISSN: 0041-624X; 1874-9968
• DOI: 10.1016/j.ultras.2008.04.011

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.