一种实时模拟血管中引导线变形的有限元模型

为了实时仿真微创介入手术过程中引导线在外力作用下的变形,提出了一种适合于描述纤细物体力学特性的模型.通过对引导线的仿真,医生可以在术前预演手术,并选择最佳的手术方案.模型采用多体结构离散化引导线,根据弹性理论推导出引导线的弹性能是节点位移的多项式函数,病人的血管四面体网格模型可从血管的三角面网格模型拓广得到,并将共轭梯度法能量下降的过程应用于引导线变形过程的模拟.实验结果表明:由于模型的弹性能和节点位移呈多项式函数关系,共轭梯度法的求解得到了有效的简化,模型的效率有显著提高.与目前广泛采用的显式计算模型相比不仅稳定且更快速.模型可应用于血管中引导线变形的实时仿真.

FEM model for real-time guide wire simulation in vasculature

A model suitable for describing the mechanical response of thin elastic objects is proposed to simulate the deformation of guide wires in minimally invasive interventions.The main objective of this simulation is to provide doctors an opportunity to rehearse the surgery and select an optimal operation plan before the real surgery.In this model the guide wire is discretized with the multi-body representation and its elastic energy derivate from elastic theory is a polynomial function of the nodal displacements.The vascular structure is represented by a tetrahedron mesh extended from the triangular mesh of the artery,which can be extracted from the patient's CT image data.The model applies the energy decline process of the conjugate gradient method to the deformation simulation of the guide wire.Experimental results show that the polynomial relationship between elastic energy and nodal displacements tremendously simplifies the evaluation of the conjugate gradient method and significantly improves the model's efficiency.Compared with models depending on an explicit scheme for evaluation,the new model is not only non-conditionally stable but also more efficient.The model can be applied to the real-time simulation of guide wire in a vascular structure.