中文摘要：

本文利用有限元法对生物软组织的超声弹性成像进行仿真研究.通过改变组织内部杨氏模量分布及数值大小,仿真计算出各种不同情形时的位移和应变分布,并对仿真结果进行分析.在考虑生物组织粘弹性的基础上,优化了组织模型,仿真更接近真实情况.仿真结果表明,利用微小应变压缩法可以实现对离体组织的弹性分布成像,考虑粘弹性的仿真结果显示组织内部的应力、应变及位移变化均为时间的函数.

英文摘要：

Biological soft tissue elasticity imaging using ultrasound is studied in this paper.Ordinary ultrasonic imaging use acoustic impedance as the imaging parameters,which can only reflect the change and the distribution of acoustic properties of tissue.When the lesion acoustic impedance changes very little while the elasticity varies much,it is necessary to detect the change in both the acoustic and the mechanical properties of tissue using ultrasound elasticity imaging.It has been more than twenty years since the concept of elastic imaging was put forward.In order to realize the elastic properties of the soft tissue of the real-time,fast,high resolution imaging,there has been much research work on theory and clinical experiment.Elasticity imaging gradually becomes the focus of ultrasound imaging in medical field.The principle of ultrasonic elasticity imaging mainly includes the traditional elasticity imaging,radiation force imaging and shear wave imaging.The traditional elasticity imaging is a static compression method based on elasticity,in which the global elastic distribution of tissue can be obtained by strain estimation.The previous research mainly includes the principle,algorithm,signal processing,noise suppression and inverse problems etc.Radiation force imaging and shear wave imaging are new imaging methods based on acoustic radiation force,in which the local elastic information nearby the acoustic focusing can be obtained.Moving the focus position can obtain the global distribution of elastic properties.In this paper,the simulation on ultrasound elasticity imaging of biological soft tissue by using finite element method was studied.By changing the internal distribution and the values of Young＇s modulus,the displacement and strain distribution in different cases can be calculated and the simulation results are analyzed.In previous simulation and experimental study,soft tissue is considered as linear elastic model.In this paper,the tissue model is revised by adding consideration of biological tissue viscoel