摘要
目的对于生物力学领域的研究者来说,计算仿真技术已成为一种不可或缺的工具。对于这种工具的性能,至关重要的一点在于其有效模拟个性化问题方面的能力。本文将阐述能将三维数字图像(由CT、超声机或MRI扫描仪生成的)直接转换生成高精度计算模型的一种独特的非常有效的方法。方法采用的方法主要涉及:基于扫描的数据生成可输出到商业网格器中的表面模型——这种方法非常费时并且不是很精确,事实上对于复杂拓扑结构的影像数据这种方法很难处理:另外一种更加直接的方法是将几何模型的生成和网格划分一次性完成——这种方法先对感兴趣区域(三维图像分割)进行识别分割,然历直接生成基于一种由定义的边界分割的体素的体网格,这种方法被用来在整个体模型生成四面体和/或六面体单元,从而直接划分网格。结果采用一种基于图像的网格方法来处理问题是非常先进的,也是非常精确有效的。这种基于图像自动生成的网格,其有限元单元模型区域边界正好在等值面上因此其考虑了局部体效应从而能保证局部体素的精确度。结论对影像数据进行网格化是挑战也是机遇,这种与以往方法思想不一样的方法,在很多例子中,获得了更好的结果。这种能简易生成精确模型的方法,对于当前很多数值分析难以处理的问题诸如血液流体和病人个性化假体设计等提供了新的解决方案。
Objective Computational simulation technology has become an indispensable tool for researchers across the biomechanics discipline. Crucial to the effectiveness of such a tool is its ability to efficiently simulate patient-specific problems. This paper will present a unique and exceptionally efficient approach that converts 3D digital images （provided typically by CT, Ultrasound or MRI scanners） directly into highly accurate computational models. Method The majority of approaches adopted have involved generating a surface model （either in a discretized or continuous format） from the scan data, which is then exported to a commercial mesher - a process which is time consuming, not very robust and virtually intractable for the complex topologies typical of image data. A more ＇direct approach＇ is to combine the geometric detection and mesh creation stages in one process. This approach involves identifying volumes of interest （segmentation of 3D image） and then directly generating the volumetric mesh based on an orthotropic grid intersected by interfaces defining the boundaries. This methodology is used that generates 3D hexahedral or tetrahedral elements throughout the volume of the domain, thus creating the mesh directly. Results Treating the problem using an image-based meshing approach is remarkably straightforward, robust, accurate and efficient. Indeed meshes can be generated automatically which is of image-based accuracy with domain boundaries of the finite element model lying exactly on the iso-surfaces thereby taking into account partial volume effects and providing sub-voxel accuracy. Conclusion Meshing from image data presents a number of challenges but also unique opportunities so that a conceptually different approach can provide, in many instances, better results thantraditional approaches. The ease and accuracy with which models can be generated opens up a wide range of previously difficult or intractable problems to numerical analysis, including blood flow, and patient-specific implant design.
出处
《医用生物力学》
EI
CAS
CSCD
2008年第1期31-36,共6页
Journal of Medical Biomechanics
关键词
生物医学模型
图像处理
网格生成
有限元分析
计算流体动力学
骨科
血液流动
Biomedical modeling
Image processing
Image-based meshing
Finite element analysis （FEA）
Computational fluid dynamics （CFD）
Orthopaedics
Blood flow
