股骨头坏死有限元模型的建立

背景：股骨头坏死有限元分析法已经被许多研究者应用，但作为分析的数字模型还存在几何以及物理相似性不够等不足。 目的：借助股骨头坏死患者的CT扫描图片建立更加逼真的股骨头坏死有限元模型。 方法：将以各向同性扫描所得的层厚0.625 mm股骨头坏死髋关节连续断层142层Dicom格式CT图像，直接读入Mimics后界定骨组织阈值、提取各层面轮廓线、图像边缘分割、选择性编辑及补洞处理，去除冗余数据，三维化处理后获得股骨头坏死三维几何面网格模型，将其保存为后缀名.lis的Ansys文件，直接导入Ansys有限元分析软件进行体网格划分，再将体网格转入Mimics根据CT值给予赋值，再次导入Ansys 生成有限元模型。 结果与结论：快捷建立了外形逼真、计算精确的股骨头坏死三维有限元模型。提示应用精细CT扫描技术，Mimics软件根据CT值直接赋值使股骨头坏死三维有限元模型的建立更加快捷、精确。

Constructing a finite element model of osteonecrosis of the femoral head

BACKGROUND: Osteonecrosis of the femoral head is a difficult and complicated case in clinical orthopedics. Its incidence and treatment are related to bio-mechanical problems, Biomechanical study plays a great role to further treatment of the disease. OBJECTIVE:To construct a three-dimensional finite element model of osteonecrosis of the femoral head based on CT images. METHODS: The 142-layer of 0.625-mm-thick consecutive CT Dicom format images of osteonecrosis of the femoral head making use of thin layer scanning technique was directly read into the Mimics software. The following procedures were: Defining bone organization threshold, withdrawing each outline, partitioning each edge of layer picture, editing selectively and repairing by hole processing. After redundancy data were cleaned, the three-dimensional geometry model of osteonecrosis of the femoral head was acquired. Then area mesh could be kept as the document Ansys named. lis as the suffix and be introduced into Ansys software directly to mesh body, and then the body mesh was transferred to Mimics to assignment on the basis of CT values, once again import Ansys to establish 3-D finite element model. RESULTS AND CONCLUSION:A realistic appearance and calculation accuracy three-dimensional finite element model of osteonecrosis of the femoral head was established. The results showed that based on sophisticated CT scanning technique and Mimics software can directly assign values, which make the establishment of three-dimensional finite element models of osteonecrosis of the femoral head faster and more accurate.