基于髋关节CT图像三维实体髋骨重建及髋骨承受力数据有限元分析

Finite element analysis of three-dimensional entity reconstruction of hip joint based on CT image and hip bearing capacity data

背景:髋骨的解剖结构与受力复杂,传统的X 射线片及CT 扫描等二维影像检查在髋骨诊断中具有一定的局限性。目的:在CT 图像的基础上,找寻一种生物骨骼实体模型准确且快捷的重建方法,研究人体内髋骨的受力情况,建立出术前优化髋关节模型,以便3D 打印。方法:采集1 例患者的髋关节CT 图像(实验已获包头医学院第一附属医院伦理批准,受试者对实验知情同意),使用核心医学Mimics 软件,从光学图像和噪声点中找出髋关节CT 图像,并且获得矢量断层图像,人工仔细分离后拟合多层图像,形成3D 图像结构。之后,在Geomagic 软件中完成对模型的曲面拟合,与此同时生成曲面和实体化。最后,在Abaqus 软件中完成髋关节的网格划分,模型赋值和有限元模拟分析。至此,完成从原始CT 到实体的所有数据转换,同时使用Anybody 软件用于模拟人体步态模拟,进行有限元分析。结果与结论:使用最简单方法完成了CT 图像的重建,经过Geomagic 完成曲面拟合并得到了良好的髋骨模型,通过Anybody 逆动力学分析得到了重要的髋骨承受力数据,得到体内承受力较大的地方为髋骨远端处,有限元分析验证了此结果。

BACKGROUND: Due to complex anatomical structure and stress of hip, traditional X-ray and CT scanning have some limitations in the diagnosis of hip. OBJECTIVE: To find an accurate and fast reconstruction method for the entity model of biological skeleton based on CT image, and to study the stress of the human hip bone, and to establish the optimized hip joint model before operation for three-dimensional printing.METHODS: CT images of hip joint were obtained from one patient (the study was approved by the Ethics Committee of First Affiliated Hospital of Baotou Medical College, and the subject signed the informed consent). The model optical images of human body were developed by medical Mimics software. The reverse design steps of “original CT image-image processing-surface reconstruction-materialization” were adopted. The necessary forward design method needed therein. Firstly, using the core medical Mimics software, the CT image of hip joint was found out from the optical image and noise point, and the vector tomography image was obtained. After carefully separating the image, the multi-layer image was fitted to form three-dimensional image structure. Then in Geomagic software, the surface fitting of the model is completed, and at the same time, Generate surfaces and materialize. In Geomagic Studio software, in order to achieve the precision of the model, it is necessary to make the surface smooth and curve smooth by command, and to meet the requirements of subsequent finite element analysis. Finally, the mesh division, model assignment and finite element analysis of hip joint are completed in Abaqus software. At this point, all the data conversion from the original CT to the entity is completed. At the same time, the Anybody software was used to simulate the human gait simulation, and the data were applied to the finite element analysis of ABAQUS. RESULTS AND CONCLUSION: The simplest method was used to complete the reconstruction of CT images, and a good hip model was obtained by Geomagic surface fitting. The important data of hip bearing capacity were obtained by Anybody inverse dynamics analysis. Finite element analysis verifies this result.