面向磁共振弹性成像的数值建模与仿真研究

摘要

磁共振弹性成像技术能够定量可视化人体组织的生物力学属性,正逐步成长为一种新型的医学成像手段.然而,其研发不仅要深入探索弹性波的产生、传播及耗散特性,而且需要建立特殊的磁共振成像装备.建立数值模型并开发仿真实验系统,可以有效促进磁共振弹性成像研究工作的开展.本文首先对人体组织进行弹性力学分析,得到外力作用下人体组织的运动微分方程,并利用有限元法求解该方程.同时建立了不同结构和弹性分布的人体组织数值模型.采用剪切弹性波作为成像探针,并根据人体组织的运动微分方程,仿真计算得到弹性波在组织中的传播信息.通过比较不同模型的估算值和理论值,验证了仿真实验系统的有效性和可靠性,说明建立的数值模型可以有效支撑磁共振弹性成像研究.%Magnetic resonance elastography (MRE) is emerging to virtually palpate human body and visualize tissue elasticity.Although MRE receives more and more attention in clinic,the study is limited due to the inaccessibility and expensiveness of magnetic resonance scanning.A numerical model is thus proposed by analyzing tissue elasticity and the forced movement differential equation.The finite element method (FEM) is introduced to resolve this numerical model of MRE.Its performance is validated with different models of tissue structure and elasticity composition.The results of quantitative experiments confirm that the new model is effective to promote numerical MRE study.