Principal trabecular structural orientation predicted by quantitative ultrasound is strongly correlated with μFEA determined anisotropic apparent stiffness.
Principal trabecular structural orientation predicted by quantitative ultrasound is strongly correlated with μFEA determined anisotropic apparent stiffness.
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DOI：
10.1007/s10237-013-0547-3
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发表时间：
2014-10
影响因子：
3.5
通讯作者：
Qin, Yi-Xian
中科院分区：
文献类型：
--
作者：
Lin, Liangjun;Oon, Han Yuen;Lin, Wei;Qin, Yi-Xian
松质骨的微结构和排列适应于施加于其上的特定机械环境。由于这种各向异性的机械特性，在评估松质骨质量和骨折风险预测时必须考虑测量方向。定量超声（QUS）已被证明能够预测骨小梁的主要结构方向（PSO）。虽然PSO的QUS预测与μCT非常接近，但仍存在一定的角度差异。这种角度差异是否会导致机械性能的显著差异仍然是未知的。本研究的目的是评估不同方法预测的不同PSO的力学性能，QUS和μCT，从而研究QUS作为无创预测松质骨PSO的方法的能力。通过验证QUS预测松质骨PSO的能力，这对于未来的QUS应用是有益的，因为PSO中的QUS测量可以提供与机械性能比与其他方向更相关的信息。在这项研究中，7个来自牛股骨远端的松质骨球被用于基于三维μCT图像生成有限元模型。在有限元分析（FEA）中，在6个不同方向（3个解剖方向，QUS预测的2个PSO和μCT计算的平均截距长度（MIL）张量的最长向量）对骨球模型进行单轴压缩加载。基于载荷下骨球的反作用力计算刚度，von Mises应力结果表明，QUS预测的PSO中的力学性能均显著高于解剖方向，并且与MIL张量的最长向量比较接近。通过QUS预测的PSO中的刚度也与MIL张量方向中的刚度高度相关（ATTmax与MIL，R2=0.98，p<001; UVmax与MIL，R2=0.92，p<001）。这些结果通过对骨球样本进行体外力学测试进行了验证。这项研究表明，由QUS预测的松质骨的PSO具有与μCT预测的方向同样强的表观刚度。
The microarchitecture and alignment of trabecular bone adapts to the particular mechanical milieu applied to it. Due to this anisotropic mechanical property, measurement orientation has to be taken into consideration when assessing trabecular bone quality and fracture risk prediction. Quantitative ultrasound (QUS) has demonstrated the ability in predicting the principal structural orientation (PSO) of trabecular bone. Although the QUS prediction for PSO is very close to that of μCT, certain angle differences still exist. It remains unknown whether this angle difference can induce significant differences in mechanical properties or not. The objective of this study is to evaluate the mechanical properties in different PSOs predicted using different methods, QUS and μCT, thus to investigate the ability of QUS as a means to predict the PSO of trabecular bone noninvasively. By validating the ability of QUS to predict the PSO of trabecular bone, it is beneficial for future QUS applications because QUS measurements in the PSO can provide information more correlated with the mechanical properties than with other orientations. In this study, seven trabecular bone balls from distal bovine femurs were used to generate finite element models based on the 3-dimensional μCT images. Uniaxial compressive loading was performed on the bone ball models in the finite element analysis (FEA) in 6 different orientations (three anatomical orientations, two PSOs predicted by QUS and the longest vector of mean intercept length (MIL) tensor calculated by μCT). The stiffness was calculated based on the reaction force of the bone balls under loading and the von Mises stress results showed that both the mechanical properties in the PSOs predicted by QUS is significantly higher than the anatomical orientations and comparatively close to the longest vector of MIL tensor. The stiffness in the PSOs predicted by QUS is also highly correlated with the stiffness in the MIL tensor orientation (ATTmax vs. MIL, R2=0.98, p<001; UVmax vs. MIL, R2=0.92, p<001). These results were validated by in vitro mechanical testing on the bone ball samples. This study demonstrates that the PSO of trabecular bone predicted by QUS has an equally strong apparent stiffness with the orientation predicted by μCT.