股骨三维有限元快速建模及骨密度值求解的初步研究

Fast Establishment of Three-dimensional Finite Element Model of Femur and Measurement of Bone Mineral Density

目的运行Ansys命令流文件快速建立股骨三维有限元模型,完成股骨骨密度值的精确求解并进行验证。方法对12侧完整的新鲜成人尸体股骨标本,采用真实测量方法(真实测量组)与有限元分析方法(有限元分析组)测量骨密度值。有限元分析组进行高速薄层CT扫描、Mask文件编辑、初步三维重建、表面光滑处理、输出股骨三维模型、运行Ansys命令流文件1完成网格划分,在Mimics中对股骨三维模型赋予材料属性,完成有限元建模、分析,运行Ansys命令流文件2及文件3,读取体单元的数值及体积,在Excel中完成体单元的体积统计,与相应的密度值的乘积即为各材料属性的质量,从Mimics中直接读取三维模型的体积,求得骨密度值。真实测量组将股骨标本以电子天平精确称重后计算真实骨密度值。2组骨密度值的数据进行单因素方差分析。结果快速完成了12侧股骨标本有限元建模并完成简易的有限元分析;2组骨密度值比较差异无统计学意义(P=0.447)。结论使用Ansys命令流文件的方法可以提高有限元建模的效率;在完成有限元建模的同时可获取精确的骨密度值。

Objective To establish a three-dimensional finite element model of femur using the finite element code Ansys,and to confirm and calculate the precise bone mineral density.Methods Bone mineral density was detected in 12 complete and fresh femurs from adult corpses using authentic measurement method（authentic measurement group） and finite element analysis（finite element analysis group）.Experimental procedures in authentic measurement group included high-speed thin-section CT scan,compilation of mask files,preliminary three-dimensional reconstruction,treatment for surface smoothness,output of the femoral three-dimensional model,partition of grid under command stream of Ansys,achievement of material properties in Mimics,completion and analysis of finite element modeling,running file 2 and file 3 under command stream of Ansys,achievement of the volume and value,statistics of volume using Excel,calculation of material mass by the volume multiplying the relevant density value,achievement of the volume in Mimics,calculation of mineral density value.In authentic measurement group,true density value was obtained after precise measurement of femur weight with an electronic balance.One-way ANOVA was performed to compare data between the two groups.Results Fast establishment of three-dimensional finite element model of femur was achieved and simple finite element analysis was completed.There was no significant difference in bone density between the two groups（P=0.447）.Conclusion Three-dimensional finite element can be effectively established by using files under command stream of Ansys.The bone mineral density can be precisely obtained with the establishment of finite element model.