QCT-based finite element models predict human vertebral strength in vitro significantly better than simulated DEXA
QCT-based finite element models predict human vertebral strength in vitro significantly better than simulated DEXA
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DOI：
10.1007/s00198-011-1568-3
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发表时间：
2012-02-01
影响因子：
4
通讯作者：
Zysset, P.
中科院分区：
文献类型：
--
作者：
Dall'Ara, E.;Pahr, D.;Zysset, P.
虽然双能X线吸收测定法（DXA）被认为是体内评估骨折风险的金标准，但在本研究中，基于定量计算机断层扫描（QCT）的有限元建模已被发现可提供体外椎体强度的定量和显著改善的预测。然而，考虑到QCT所需的辐射剂量要大得多，这种技术可能会在体内使用。骨密度（BMD）是评价体内骨折风险的金标准。基于QCT的有限元（FE）建模是一种预测椎体强度的工程方法。本研究的目的是比较FE和临床诊断工具预测椎体强度的能力，在体外使用改进的测试protocol.37椎体切片扫描与QCT和高分辨率周边QCT（HR-pQCT）。评价两种分辨率下的骨矿物质含量（BMC）、总BMD（tBMD）、侧位（aBMD-lat）和前后位（aBMD-ap）投影的面积BMD。然后使用新型测试装置在每个样本中诱导楔形断裂。分别从QCT和HR-pQCT图像生成非线性均匀化FE模型（hFE）和线性微FE（mu FE）。对于实验和模型，（刚度、极限载荷）和材料性能hFE和mu FE模型对材料性能的预测优于结构模型，对强度的预测明显优于QCT和HR-pQCT计算的aBMD（hFE：RA（2）= 0.79，mu FE：RA（2）= 0.88，aBMD-ap：RA（2）= 0.48-0.47，aBMD-lat：RA（2）aEuro千分率= 0.41-0.43）。此外，hFE提供了合理的定量估计的实验力学性能，而无需拟合的模型parameters.The QCT为基础的hFE方法提供了一个定量的和显着改善的预测椎体强度在体外相比，模拟DXA。这种上级预测能力需要在模拟人体椎骨体内情况的载荷条件下进行验证。
While dual energy X-ray absorptiometry (DXA) is considered the gold standard to evaluate fracture risk in vivo, in the present study, the quantitative computed tomography (QCT)-based finite element modeling has been found to provide a quantitative and significantly improved prediction of vertebral strength in vitro. This technique might be used in vivo considering however the much larger doses of radiation needed for QCT.Vertebral fracture is a common medical problem in osteoporotic individuals. Bone mineral density (BMD) is the gold standard measure to evaluate fracture risk in vivo. QCT-based finite element (FE) modeling is an engineering method to predict vertebral strength. The aim of this study was to compare the ability of FE and clinical diagnostic tools to predict vertebral strength in vitro using an improved testing protocol.Thirty-seven vertebral sections were scanned with QCT and high resolution peripheral QCT (HR-pQCT). Bone mineral content (BMC), total BMD (tBMD), areal BMD from lateral (aBMD-lat), and anterior-posterior (aBMD-ap) projections were evaluated for both resolutions. Wedge-shaped fractures were then induced in each specimen with a novel testing setup. Nonlinear homogenized FE models (hFE) and linear micro-FE (mu FE) were generated from QCT and HR-pQCT images, respectively. For experiments and models, both structural properties (stiffness, ultimate load) and material properties (apparent modulus and strength) were computed and compared.Both hFE and mu FE models predicted material properties better than structural ones and predicted strength significantly better than aBMD computed from QCT and HR-pQCT (hFE: RA(2) = 0.79, mu FE: RA(2) = 0.88, aBMD-ap: RA(2) = 0.48-0.47, aBMD-lat: RA(2)aEuro parts per thousand= 0.41-0.43). Moreover, the hFE provided reasonable quantitative estimations of the experimental mechanical properties without fitting the model parameters.The QCT-based hFE method provides a quantitative and significantly improved prediction of vertebral strength in vitro when compared to simulated DXA. This superior predictive power needs to be verified for loading conditions that simulate even more the in vivo case for human vertebrae.