Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China.
Department of Spinal Surgery, Beijing Jishuitan Hospital, Beijing 100035, China.
Med Eng Phys. 2022 Oct;108:103882. doi: 10.1016/j.medengphy.2022.103882. Epub 2022 Aug 28.
Biomechanical CT (BCT), i.e., quantitative computed tomography-based finite element analysis (QCT-FEA), promises an improved technique over bone mineral density (BMD) in predicting bone strength and the risk of osteoporotic vertebral fractures. However, most of the BCT models only consider a uniform compressive loading condition and they have not been validated for Chinese subjects. This study examined the ability of BCT to predict wedge fracture-related vertebral flexion strength in a cohort of Chinese cadaveric vertebrae. Twelve human vertebrae were scanned with dual energy X-ray absorptiometry (DXA) and QCT to measure areal and volumetric BMD, respectively. To produce wedge fractures, the cadaveric vertebrae were experimentally loaded until failure under a 15 flexion. Vertebral flexion stiffness and strength were measured from the force-displacement curve. Voxel-based heterogeneous FE models of the vertebrae were created and virtually tested in uniform compression and 15 flexion to compute compressive and flexion strength (and stiffness), respectively. The predictions of vertebral flexion strength with BMD or BCT measures were evaluated with linear regression analyses. Results showed weak correlations between experimentally-measured flexion strength vs. DXA-aBMD (R = 0.26) or QCT-vBMD (R = 0.39). However, there were strong correlations between experimentally-measured flexion strength vs. BCT-computed vertebral strength under either flexion (R = 0.71) or compression (R = 0.70) loading conditions, although flexion reduced the BCT-computed vertebral strength by 9.2%. These results suggest that, regardless of whether a uniform compression or a flexion loading is simulated, BCT can predict in vitro vertebral flexion strength better than BMD.
生物力学 CT（BCT），即基于定量计算机断层扫描的有限元分析（QCT-FEA），有望成为一种优于骨密度（BMD）的技术，用于预测骨强度和骨质疏松性椎体骨折的风险。然而，大多数 BCT 模型仅考虑均匀压缩载荷条件，并且尚未针对中国受试者进行验证。本研究考察了 BCT 在预测中国人椎体楔形骨折相关前屈强度方面的能力。对 12 个人体椎体进行双能 X 射线吸收法（DXA）和 QCT 扫描，分别测量面积和体积 BMD。为了产生楔形骨折，将尸体椎体在 15°前屈下进行实验加载直至破坏。从力-位移曲线上测量椎体前屈刚度和强度。基于体素的椎体异质有限元模型被创建，并在均匀压缩和 15°前屈下进行虚拟测试，以分别计算压缩强度和前屈强度（和刚度）。通过线性回归分析评估了 BMD 或 BCT 测量值与椎体前屈强度的预测关系。结果表明，实验测量的前屈强度与 DXA-aBMD（R=0.26）或 QCT-vBMD（R=0.39）之间的相关性较弱。然而，实验测量的前屈强度与 BCT 计算的椎体在两种载荷条件下（前屈 R=0.71，压缩 R=0.70）均具有很强的相关性，尽管前屈降低了 BCT 计算的椎体强度 9.2%。这些结果表明，无论模拟均匀压缩还是前屈载荷，BCT 都可以比 BMD 更好地预测体外椎体前屈强度。
