超声波场中造影剂包膜气泡的界面稳定性研究

项目名称： 超声波场中造影剂包膜气泡的界面稳定性研究

项目编号： No.11302128

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 刘筠乔

作者单位： 上海交通大学

项目金额： 26万元

中文摘要： 造影剂包膜气泡的界面稳定性是决定超声灌注成像质量的关键。目前对包膜气泡稳定性的研究多局限于单个气泡模型，而对气泡群的稳定性研究多局限于一般的无包膜气泡。本研究拟建立多个粘弹性包膜气泡与超声波粘性可压缩流场相耦合的稳定性分析平台。运用多时间尺度的理论分析方法，研究零阶（径向振动）、一阶（平移运动）和高阶（形状振动）各阶模态之间的非线性共振关系，结合外加超声波的频率、强度、波形等参数，得出包膜气泡界面不稳定产生的条件。运用基于浸入边界法的流固耦合数值模拟程序实现对包膜气泡界面的捕捉，模拟真实超声波场中气泡各阶模态的非线性发展过程，讨论气泡群中周围气泡的相对平移运动、形状振动及血管壁的受限环境对界面稳定性的干扰作用，分析流场粘性对稳定性的影响。本项目为通过控制包膜和超声波的物理参数以提高成像效率的方法提供科学依据，对超声造影剂的制备和超声灌注成像技术的完善具有指导意义。

中文关键词： 流固耦合；气泡相互作用；粘弹性膜；界面稳定性；模态共振关系

英文摘要： Encapsulated bubbles are widely used in medical ultrasound applications, e.g. ultrasound perfusion imaging. The stability of the encapsulating membrane exposed in an ultrasound field is of importance in the ultrasound contrast agents. The deformation induced by the ultrasonic pressure wave may lead to the break-up of a bubble, and thereby shorten the residence time of contrast agents. Most of the existing studies on the stability of the encapsulated bubble were confined to the single-bubble model, while the previous studies on the stability of the bubbles mainly focused on gas bubbles without encapsulating membranes. The objective of this study is to establish an analytical model of the stabilities of multi-bubbles encapsulated with viscoelastic membranes under the viscous and compressible ultrasound field. In the theoretical study, we will utilize the homogenization methods to investigate the nonlinear resonance relationship among the zeroth-order (the radial motion), the first-order (the translation motion) and the higher-order (the shape deformation) oscillations, and their resonance interactions with the driving ultrasound, respectively. Accordingly, we will obtain the conditions under which the surface of the encapsulated bubbles would become unstable. The parameters of the ultrasound, such as the frequency

英文关键词： fluid-structure interaction；bubble-bubble interaction；viscoelastic membrane；surface stability；resonanace interaction