Simulations of ultrasound propagation in random arrangements of elliptic scatterers: Occurrence of two longitudinal waves
| Autor: | Blandine Dobigny, Emmanuel Bossy, Fabien Mézière, Arnaud Derode, Marie Muller |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
Shear waves
Time Factors Acoustics and Ultrasonics Wave propagation Acoustics Physics::Medical Physics Bone and Bones Motion Arts and Humanities (miscellaneous) Pressure Animals Humans Scattering Radiation Computer Simulation Ultrasonics Anisotropy Ultrasonography Physics Scattering Finite difference method Reproducibility of Results Numerical Analysis Computer-Assisted Models Theoretical Ellipsoid Computational physics Sound Monte Carlo Method Structural acoustics Longitudinal wave |
| Zdroj: | The Journal of the Acoustical Society of America. 133:643-652 |
| ISSN: | 0001-4966 |
| DOI: | 10.1121/1.4774276 |
| Popis: | Ultrasound propagation in clusters of elliptic (two-dimensional) or ellipsoidal (three-dimensional) scatterers randomly distributed in a fluid is investigated numerically. The essential motivation for the present work is to gain a better understanding of ultrasound propagation in trabecular bone. Bone microstructure exhibits structural anisotropy and multiple wave scattering. Some phenomena remain partially unexplained, such as the propagation of two longitudinal waves. The objective of this study was to shed more light on the occurrence of these two waves, using finite-difference simulations on a model medium simpler than bone. Slabs of anisotropic, scattering media were randomly generated. The coherent wave was obtained through spatial and ensemble-averaging of the transmitted wavefields. When varying relevant medium parameters, four of them appeared to play a significant role for the observation of two waves: (i) the solid fraction, (ii) the direction of propagation relatively to the scatterers orientation, (iii) the ability of scatterers to support shear waves, and (iv) a continuity of the solid matrix along the propagation. These observations are consistent with the hypothesis that fast waves are guided by the locally plate/bar-like solid matrix. If confirmed, this interpretation could significantly help developing approaches for a better understanding of trabecular bone micro-architecture using ultrasound. |
| Databáze: | OpenAIRE |
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