Quantitative computed tomography-based finite element models of the human lumbar vertebral body: Effect of element size on stiffness, damage, and fracture strength predictions
Quantitative computed tomography-based finite element models of the human lumbar vertebral body: Effect of element size on stiffness, damage, and fracture strength predictions
复制标题
DOI：
10.1115/1.1589772
复制
发表时间：
2003-08-01
影响因子：
1.7
通讯作者：
Keaveny, TM
中科院分区：
文献类型：
--
作者：
Crawford, RP;Rosenberg, WS;Keaveny, TM
本研究调查了14个离体人尸体腰椎椎体（年龄：37-87; M=6，F=8），从临床类型的CT扫描自动生成的特定的“基于体素”的有限元模型的数值收敛特性。考虑到最终的临床应用，还评估了模型刚度预测实验测量的椎体压缩断裂强度的能力。“低”分辨率模型（3 × 3 × 3 mm元件尺寸）的刚度平均仅比“高”分辨率模型（1 × 1 × 1.5 mm）高4%（p=0.03），尽管样本间差异超过4倍。在对应于0.5%总应变的载荷下，使用低分辨率与高分辨率模型进行的损伤预测存在显著差异（p=0.01）。高（r（2）=0.94）和低（r（2）=0.92）分辨率模型刚度值与实验测量的极限强度值高度相关。由于椎体刚度的变化在人口中是远远大于那些所产生的体素大小的差异，这些结果表明，成像分辨率是不关键的横截面研究的这个参数。然而，纵向研究，试图跟踪更微妙的变化，随着时间的推移，刚度应占小，但非常显着的影响体素大小。这些结果也表明，一个自动化的基于体素的有限元建模技术可以提供一个很好的非侵入性评估椎体强度。
This study investigated the numerical convergence characteristics of specimen-specific "voxel-based" finite element models of 14 excised human cadaveric lumbar vertebral bodies (age: 37-87; M=6, F=8) that were generated automatically from clinical-type CT scans. With eventual clinical applications in mind, the ability of the model stiffness to predict the experimentally,measured compressive fracture strength of the vertebral bodies was also assessed. The stiffness of "low"-resolution models (3X3X3 mm element size) was on average only 4% greater (p=0.03) than for "high"-resolution models (1X1X1.5 mm) despite interspecimen variations that varied over four-fold. Damage predictions using low- vs high-resolution models were significantly different (p=0.01) at loads corresponding to an overall strain of 0.5%. Both the high (r(2)=0.94) and low (r(2)=0.92) resolution model stiffness values were highly correlated with the experimentally measured ultimate strength values. Because vertebral stiffness variations in the population are much greater than those that arise from differences in voxel size, these results indicate that imaging resolution is not critical in cross-sectional studies of this parameter. However longitudinal studies that seek to track more subtle changes in stiffness over time should account for the small but highly significant effects of voxel size. These results also demonstrate that an automated voxel-based finite element modeling technique may provide an excellent noninvasive assessment of vertebral strength.