Kim Sang-Hyuk, Suh Hyun Sang, Cho Min Hyoung, Lee Soo Yeol, Kim Tae-Seong
Department of Biomedical Engineering, Kyung Hee University, Yongin, Gyeonggi, Republic of Korea.
Annu Int Conf IEEE Eng Med Biol Soc. 2009;2009:436-9. doi: 10.1109/IEMBS.2009.5334707.
Osteoporosis is a serious bone disease which leads to the increased risk of bone fractures. For prevention and therapy, early detection of osteoporosis is critical. In general, for diagnosis of osteoporosis, dual-energy X-ray absoptiometry (DXA) or densitometry is most commonly used. However DXA exhibits some disadvantages such as ionizing radiation, relatively expensive cost, and limited information on mineralization and geometry of the bone. As an alternative method of DXA, quantitative ultrasound (QUS) is being investigated. In contrast to DXA, QUS is non-ionizing and relatively inexpensive. It can also provide some bone-related parameters (e.g., quantitative measurements including speed of sound and frequency-dependent attenuation). However the estimation of these parameters is difficult and few analytical solutions exist due to the complex behavior of ultrasound propagation in bone. As an alternative to the analytical methods, in most attempts, finite difference time domain (FDTD) method is used for simulation of ultrasound propagation in bone with a limited capability of modeling complex geometries of the bone. Finite element method (FEM) is a better solution since it can handle the complex geometry, but has been rarely applied due to its computational complexity. In this work, we propose an approach of FEM-based simulation of ultrasound propagation in bone. To validate our approach, we have tested simulated and real bone models from micro-CT using the index of speed-of-sound. Our results achieve an average of 97.54% in the computational accuracy.
骨质疏松症是一种严重的骨骼疾病，会导致骨折风险增加。对于预防和治疗而言，早期检测骨质疏松症至关重要。一般来说，在骨质疏松症的诊断中，最常用的是双能X线吸收法（DXA）或骨密度测定法。然而，DXA存在一些缺点，如电离辐射、成本相对较高，以及关于骨矿化和骨几何形状的信息有限。作为DXA的替代方法，定量超声（QUS）正在被研究。与DXA不同，QUS是非电离的且相对便宜。它还可以提供一些与骨相关的参数（例如，包括声速和频率依赖性衰减的定量测量）。然而，由于超声在骨中传播的复杂行为，这些参数的估计很困难，并且几乎没有解析解。作为解析方法的替代方案，在大多数尝试中，时域有限差分（FDTD）方法被用于模拟超声在骨中的传播，但对骨复杂几何形状的建模能力有限。有限元方法（FEM）是一个更好的解决方案，因为它可以处理复杂的几何形状，但由于其计算复杂性很少被应用。在这项工作中，我们提出了一种基于有限元方法模拟超声在骨中传播的方法。为了验证我们的方法，我们使用声速指标测试了来自微型计算机断层扫描（micro-CT）的模拟和真实骨模型。我们的结果在计算精度上平均达到了97.54%。
