真实血管组织的力学特性分析与物理建模

发布时间：2018-03-25 18:50

本文选题：虚拟手术　切入点：血管　出处：《河北大学》2017年硕士论文

【摘要】：心脑血管疾病的发病率和死亡率逐年增高,已成为危害人类健康的主要杀手。而血管介入手术是其主要的诊疗手段,因此提高临床介入医生的手术水平是整体提高心脑血管疾病诊疗水平的重要一环。随着虚拟仿真技术的革新,虚拟血管介入手术训练系统已经成为培训医生的一种有效的办法,有着低成本、无损伤性、可重复性和可指定性的巨大优势。虚拟血管介入手术系统关键在于仿真的实时性与精确度,而传统的物理建模手术训练系统缺少血管弹性特性,也没有对导管导丝介入后,血管内壁的穿刺力学行为进行深入研究。针对现有问题,本文的主要研究内容包括以下三点:第一,基于真实血管的物理实验参数获取。由于血管具有较复杂的物理特性,为了得到精确的血管的弹性模量,设计了真实血管轴向拉伸实验,应用最小二乘法拟合血管发生微小形变下的应力-应变曲线,求出血管的弹性模量值。第二,对不同角度穿刺下血管壁的力学行为进行研究,发现了规律,提出了一个新的数学模型。本文对真实猪心血管进行大量实验,分别对探针以15°、30°、45°、60°、90°穿刺血管内壁时获得的力学行为进行数据整理分析,得出了不同角度穿刺下的近似线性模型,为血管介入手术系统的建立提供了数据基础。第三,建立了一个基于质点-弹簧系统的血管物理模型。通过用真实血管测得的弹性模量,本文提出了一个等效模型,得到了真实血管的弹性模量E与质点-弹簧系统中弹性系数k的关系,创建了一套提高交互实时性的复杂血管组织物理模型。实验仿真部分用血管的有限元模型对不同角度穿刺下真实血管壁的力学行为进行仿真,发现当探针穿刺血管内壁使血管局部发生微小形变时,力学的特性分析结果和各向同性建模仿真的受力形变结果相似,可以近似的用直线来拟合,而且趋势都是随着角度的增加,弹性系数减小,精确度基本符合虚拟手术要求,在允许误差范围内。并通过有限元仿真去对比质点-弹簧模型仿真,验证了本文提出的模型在保证实时性的前提下,提高了仿真精度。
[Abstract]:The morbidity and mortality of cardiovascular and cerebrovascular diseases have been increasing year by year, which has become the main killer of human health, and vascular interventional surgery is the main means of diagnosis and treatment. Therefore, improving the operation level of clinical interventional doctors is an important link to improve the diagnosis and treatment level of cardiovascular and cerebrovascular diseases as a whole. With the innovation of virtual simulation technology, virtual vascular interventional surgery training system has become an effective way to train doctors. The virtual vascular interventional surgery system depends on the real-time and accuracy of simulation, while the traditional physical modeling surgery training system lacks vascular elasticity. There is also no in-depth study on the mechanical behavior of the puncture of vascular inner wall after catheter guide wire intervention. In view of the existing problems, the main research contents of this paper include the following three points: first, Based on the physical experimental parameters of real blood vessels, the axial tensile experiments of real blood vessels were designed to obtain the accurate elastic modulus of blood vessels because of the complex physical properties of blood vessels. Using the least square method to fit the stress-strain curve of blood vessel under micro deformation, the elastic modulus of blood vessel is calculated. Secondly, the mechanical behavior of vascular wall under different angle puncture is studied, and the regularity is found. A new mathematical model is proposed. In this paper, a large number of experiments have been carried out on the real pig cardiovascular system. The mechanical behavior obtained by the probe with a probe of 15 掳~ 30 掳~ 45 掳~ 60 掳~ 90 掳puncture is analyzed, and the approximate linear model under different angles of puncture is obtained. It provides a data basis for the establishment of vascular interventional surgery system. Thirdly, a physical vascular model based on mass-spring system is established. By using the elastic modulus measured by real blood vessels, an equivalent model is proposed in this paper. The relationship between the elastic modulus E of the real blood vessel and the elastic coefficient k in the mass-spring system is obtained. In this paper, a set of complex vascular tissue physical models is established to improve the real-time interaction. In the experiment, the finite element model of blood vessel is used to simulate the mechanical behavior of the real blood vessel wall under different angles of puncture. It is found that the results of mechanical properties analysis are similar to those of isotropic modeling and simulation, and can be approximated by a straight line. And the trend is that with the increase of angle, the elastic coefficient decreases, the accuracy basically accords with the requirement of virtual surgery, and within the allowable error range, the simulation of mass-spring model is compared by finite element simulation. It is verified that the proposed model improves the accuracy of simulation on the premise of ensuring real-time performance.
【学位授予单位】：河北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R815;TP391.9

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