Faculty of Engineering, Civil and Environmental Engineering Department, 3-016 Markin/CNRL Natural Resources Engineering Facility, University of Alberta, Edmonton, Alberta T6G 2W2, Canada.
Faculty of Medicine and Dentistry, 7-020D Katz Group Centre for Pharmacy and Health Research, University of Alberta, Edmonton, Alberta T6G 2E1, Canada.
Ultrasonics. 2014 Aug;54(6):1663-76. doi: 10.1016/j.ultras.2014.02.024. Epub 2014 Mar 11.
Quantitative ultrasound for bone assessment is based on the correlations between ultrasonic parameters and the properties (mechanical and physical) of cancellous bone. To elucidate the correlations, understanding the physics of ultrasound in cancellous bone is demanded. Micro-scale modeling of ultrasound propagation in cancellous bone using the finite-difference time-domain (FDTD) method has been so far utilized as one of the approaches in this regard. However, the FDTD method accompanies two disadvantages: staircase sampling of cancellous bone by finite difference grids leads to generation of wave artifacts at the solid-fluid interface inside the bone; additionally, this method cannot explicitly satisfy the needed perfect-slip conditions at the interface. To overcome these disadvantages, the finite element method (FEM) is proposed in this study. Three-dimensional finite element models of six water-saturated cancellous bone samples with different bone volume were created. The values of speed of sound (SOS) and broadband ultrasound attenuation (BUA) were calculated through the finite element simulations of ultrasound propagation in each sample. Comparing the results with other experimental and simulation studies demonstrated the capabilities of the FEM for micro-scale modeling of ultrasound in water-saturated cancellous bone.
骨定量超声评估基于超声参数与松质骨物理和力学特性之间的相关性。为了阐明这些相关性，需要了解超声在松质骨中的物理特性。迄今为止，使用有限差分时域（FDTD）方法对松质骨中超声传播进行微尺度建模一直是这方面的一种方法。然而，FDTD 方法有两个缺点：有限差分网格对松质骨的阶跃采样导致在骨内固液界面产生波伪影；此外，该方法不能在界面处明确满足所需的理想滑移条件。为了克服这些缺点，本研究提出了有限元法（FEM）。创建了具有不同骨体积的六个水饱和松质骨样本的三维有限元模型。通过对每个样本中超声传播的有限元模拟计算了声速（SOS）和宽带超声衰减（BUA）的值。将结果与其他实验和模拟研究进行比较，证明了 FEM 对水饱和松质骨中超声微尺度建模的能力。
