应用CT断层图像重建股骨有限元模型

目的寻求一种基于CT断层图像快速且精确地建立全股骨三维有限元模型的方法，并应用有限元分析其力学特性以评价建模方法的优势。方法在Mimics中直接读取符合Dicom3．0标准的股骨原始CT数据，经阂值设定、区域增长及形态学操作等生成股骨初始3D模型，后期结合有限元软件ANSYS生成最终的三维有限元网格模型．然后在ANSYS中分别对应用Mimics得到的模型和统一弹性模量的模型加载200N的垂直载荷，比较两者应力分布的异同。结果获得的股骨有限元模型共含有143780个节点和99650个四面体单元，其弹性模量与CT值（密度）相关分布，取值范围在6．01～15．59GPa之间。与统一弹性模量的模型相比较，应用Mimics得到的模型其应力呈现离散性分布。结论应用Mimics可以建立更符合股骨机械结构和力学性质的三维有限元模型，同时缩短了建模时间，据此模型得到的股骨力学特性分析结果更为可信，以辅助指导临床应用。

Establishment of finite element femur model with CT imaging

Objective To explore a rapid and precise method for establishing of the three-dimensional finite element model of femur with CT imaging, and evaluate the advantages of the establishment method by analyzing the biomechanic characteristics of finite element analysis. Methods The primitive femur CT data were adopted according to Dicom 3.0 standard in Mimics,obtain the primitive three-dimensional femur model was established in threshold defining,region enlarging and morphological performing. Remesh the primitive model and combined it with ANSYS software to create the final finite-element model. The model obtained by using the Mimics and the model of unified elastic modulus were loaded with 200 N vertical loading in ANSYS respectively. Then checked out the difference of their stress distribution. Results The finite element model was established including 143 780 nodes and 99 650 tetrahedrons elements,the value of elastic modulus between 6.01 GPa and 15.59 GPa. Compared with the uniform Emodulus model,the stress distribution of the model established by Mimics presented discrete patterns. Conclusion It is demonstrated that application of Mimics could establish precise three-dimensional finite element model in shorter period. Analytical results of femur biomechanic characteristics from the model is more credible, thus it is helpful in assisting clinical application.