Lu Yongtao, Engelke Klaus, Püschel Klaus, Morlock Michael M, Huber Gerd
Institute of Biomechanics, TUHH Hamburg University of Technology, Germany.
Institute of Medical Physics, University of Erlangen, Germany.
Med Eng Phys. 2014 Aug;36(8):1069-73. doi: 10.1016/j.medengphy.2014.05.001. Epub 2014 Jun 2.
Quantitative computed tomography (QCT)-based finite element (FE) models provide a better prediction of vertebral strength than dual-energy X-ray absorptiometry. However, FE models are often created from datasets acquired at different CT scan protocols and it is unclear whether this influences the FE results. The aim of this paper was to investigate whether there was an effect of the CT scan protocol on the FE models. 12 human thoracolumbar vertebrae were scanned on top of a calcium hydroxyapatite calibration phantom using a standard QCT scan protocol - 120kV, 100mAs (PA); and a low dose protocol - 90kV, 150mAs (PB). FE cancellous models with cuboid volume of interest and inhomogeneous nonlinear bone properties were created. Axial compression was simulated. The apparent BMD, modulus and yield strength showed significant differences between the two scan protocols. The apparent BMD, the modulus and yield strength between the two groups were highly linearly correlated. This paper indicated that the FE models created from image datasets acquired at different X-ray tube voltage settings would give significantly different results and this effect could be possibly corrected using a linear correction approach.
基于定量计算机断层扫描（QCT）的有限元（FE）模型比双能X线吸收法能更好地预测椎体强度。然而，有限元模型通常是根据在不同CT扫描协议下获取的数据集创建的，目前尚不清楚这是否会影响有限元分析结果。本文的目的是研究CT扫描协议对有限元模型是否有影响。使用标准QCT扫描协议（120kV，100mAs，前后位）和低剂量协议（90kV，150mAs）在羟基磷灰石校准体模上对12个成人胸腰椎椎体进行扫描。创建了具有长方体感兴趣体积和非均匀非线性骨特性的有限元松质骨模型。模拟了轴向压缩。两种扫描协议之间的表观骨密度、模量和屈服强度显示出显著差异。两组之间的表观骨密度、模量和屈服强度高度线性相关。本文表明，根据在不同X射线管电压设置下获取的图像数据集创建的有限元模型会给出显著不同的结果，并且这种影响可能可以通过线性校正方法进行校正。
