Department of Mechanical Engineering, INSIGNEO Institute for In Silico Medicine, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK.
Department of Oncology and Metabolism, MRC-Arthritis UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA), University of Sheffield, Sheffield, UK.
Biomech Model Mechanobiol. 2018 Dec;17(6):1715-1730. doi: 10.1007/s10237-018-1051-6. Epub 2018 Jul 10.
The calcaneus bone is formed of extensive trabecular bone and is therefore well suited to be used as an example of loaded bone to establish the ability of combining microfinite element (microFE) technique with high-resolution peripheral quantitative computed tomography (HR-pQCT) in determining its mechanical properties. HR-pQCT is increasingly used as a tool for in vivo bone clinical research, but its use has been limited to the distal radius and tibia. The goal of this study was to determine the applicability of HR-pQCT-derived microFE models of the calcaneus trabecular bone with 82 μm voxel size with reference to higher-resolution microCT-based models taken as gold standard. By comparing the outputs of microFE models generated from both HR-pQCT and microCT images of the trabecular bone of five calcaneus cadaveric specimens, it was found that the HR-pQCT-based models predicted mechanical properties for fracture load, total reaction force and von Mises stress are considerably different from microCT-based counterparts by 33, 64 and 70%, respectively. Also, the morphological analysis showed a comprehensive geometrical difference between HR-pQCT-based microFE models and their microCT-based equivalents. The results of the HR-pQCT-based models were found to have strong dependency on the threshold value chosen to binarise the images prior to finite element modelling. In addition, it was found that the voxel size has a strong impact on accuracy of imaged-based microFE models compared to other factors such as the presence of soft tissue and image scanning integration time. Therefore, although HR-pQCT has shown to be useful to predict overall structural and biomechanical changes, it is limited in providing local accurate biomechanical properties of trabecular bone and therefore should be used with caution when assessing bone remodelling through local changes of trabecular bone apposition and resorption in disease treatment monitoring.
跟骨由广泛的小梁骨组成，因此非常适合作为一个例子来研究微有限元 (microFE) 技术与高分辨率外周定量计算机断层扫描 (HR-pQCT) 相结合的能力，以确定其力学性能。HR-pQCT 越来越多地被用作活体骨临床研究的工具，但它的应用仅限于桡骨远端和胫骨。本研究的目的是确定具有 82μm 体素大小的 HR-pQCT 衍生跟骨小梁骨 microFE 模型的适用性，并将其与作为金标准的更高分辨率 microCT 为基础的模型进行比较。通过比较五个跟骨尸体标本的小梁骨的 HR-pQCT 和 microCT 图像生成的 microFE 模型的输出，发现基于 HR-pQCT 的模型预测的骨折载荷、总反力和 von Mises 应力的力学性能与基于 microCT 的模型相差 33%、64%和 70%。此外，形态分析显示基于 HR-pQCT 的 microFE 模型与基于 microCT 的模型之间存在全面的几何差异。基于 HR-pQCT 的模型的结果发现与在进行有限元建模之前对图像进行二值化选择的阈值值有很强的依赖性。此外，与其他因素（如软组织的存在和图像扫描积分时间）相比，发现体素大小对基于图像的 microFE 模型的准确性有很大的影响。因此，尽管 HR-pQCT 已被证明可用于预测整体结构和生物力学变化，但它在提供小梁骨的局部准确生物力学特性方面存在局限性，因此在评估疾病治疗监测过程中通过小梁骨附着和吸收的局部变化来评估骨重塑时应谨慎使用。
