Lin W, Qin Y X, Rubin C
Department of Biomedical Engineering, State University of New York at Stony Brook, 11794-2580, USA.
Ann Biomed Eng. 2001 Sep;29(9):781-90. doi: 10.1114/1.1397787.
The objective of this study was to investigate ultrasound propagation in trabecular bone by considering the wave reflection and transmission in a multilayered medium. The use of ultrasound to identify those at risk of osteoporosis is a promising diagnostic method providing a measure of bone mineral density (BMD). A stratified model was proposed to study the effect of transmission and reflection of ultrasound wave within the trabecular architecture on the relationship between ultrasound and BMD. The results demonstrated that ultrasound velocity in trabecular bone was highly correlated with the bone apparent density (r=0.97). Moreover, a consistent pattern of the frequency dependence of ultrasound attenuation coefficient has been observed between simulation using this model and experimental measurement of trabecular bone. The normalized broadband ultrasound attenuation (nBUA) derived from the simulation results revealed that nBUA was nonlinear with respect to trabecular porosity and BMD. The curve of the relationship between nBUA and BMD was parabolic in shape, and the peak magnitude of nBUA was observed at approximately 60% of bone porosity. These results agreed with the published experimental data and demonstrated that according to the stratified model, reflection and transmission were important factors in the ultrasonic propagation through the trabecular bone.
本研究的目的是通过考虑多层介质中的波反射和透射来研究超声波在松质骨中的传播。利用超声波识别骨质疏松风险人群是一种很有前景的诊断方法，可提供骨矿物质密度（BMD）的测量值。提出了一个分层模型，以研究超声波在小梁结构内的透射和反射对超声与骨密度关系的影响。结果表明，松质骨中的超声速度与骨表观密度高度相关（r = 0.97）。此外，在使用该模型进行的模拟与松质骨的实验测量之间，观察到了超声衰减系数频率依赖性的一致模式。从模拟结果得出的归一化宽带超声衰减（nBUA）表明，nBUA与松质骨孔隙率和骨密度呈非线性关系。nBUA与骨密度之间关系的曲线呈抛物线形状，nBUA的峰值出现在骨孔隙率约为60%处。这些结果与已发表的实验数据一致，并表明根据分层模型，反射和透射是超声波在松质骨中传播的重要因素。
