Miller K
Department of Mechanical and Materials Engineering, University of Western Australia, 35 Stirling Highway, Crawley/Perth WA 6009, Australia.
Biomed Sci Instrum. 2001;37:179-84.
This paper presents realistic computer simulation of deformation of the brain subject to in-vivo indentation. The work presented provides a step towards neurosurgical simulation, with applications to non-rigid registration, virtual reality training and operation planning systems and robotic devices to perform minimally invasive brain surgery. In order to properly analyze experimental data collected in-vivo, a three-dimensional, non-linear finite element model of the brain was developed. Magnetic resonance imaging techniques were used to obtain geometric information needed for the model. The shape of the force-displacement curve obtained using the numerical solution was very similar to the experimental one. The predicted forces were about 31% lower than those recorded during the experiment. Having in mind that the coefficients in the model had been identified based on experimental data obtained in-vitro, and large variability of mechanical properties of biological tissues, such agreement can be considered as very good. By appropriately increasing material parameters describing instantaneous stiffness of the tissue one is able, without changing the structure of the model, to reproduce experimental curve almost perfectly. Numerical studies showed also, that the linear, viscoelastic model of brain tissue is not appropriate for the modeling brain tissue deformation even for moderate strains.
本文介绍了对活体大脑进行压痕时大脑变形的真实计算机模拟。所展示的工作朝着神经外科模拟迈出了一步，可应用于非刚性配准、虚拟现实训练、手术规划系统以及用于进行微创脑部手术的机器人设备。为了正确分析活体收集的实验数据，开发了大脑的三维非线性有限元模型。利用磁共振成像技术获取模型所需的几何信息。使用数值解得到的力 - 位移曲线形状与实验曲线非常相似。预测力比实验记录的力低约31%。考虑到模型中的系数是基于体外获得的实验数据确定的，以及生物组织力学性能的较大变异性，这样的一致性可被视为非常好。通过适当增加描述组织瞬时刚度的材料参数，在不改变模型结构的情况下，能够几乎完美地重现实验曲线。数值研究还表明，即使对于中等应变，脑组织的线性粘弹性模型也不适用于模拟脑组织变形。
