基于有限元分析和集中参数模型微血管与超声微泡声学响应的模拟

发布时间：2018-03-30 17:41

  本文选题：微血管　切入点：造影剂　出处：《中国组织工程研究》2016年42期

【摘要】：背景:研究特定超声激励下微血管与内部单个微泡间的非线性声学响应,对于最大化超声能量的沉积,促进定量成像算法的发展,揭示损害机制或评价靶向治疗的效果,克服传统方法主要适用于大尺寸血管的局限性、测量微血管弹性意义重大。目的:构建微血管中超声微泡模型,揭示超声、微泡与血管、血流间的内在机制。方法:基于有限元分析和集中参数模型,在Comsol Multiphysics 3.5a平台上进行微血管中超声微泡三维模型构建和模拟仿真。结果与结论:(1)微泡径向运动因受近处血管壁面限制,移动速度较轴向小;而血管壁因与微泡振动耦合,近微泡的中心处位移和应力最大;(2)相同声压下,激励频率增加会减弱微血管的缩放且更快趋于稳定;在相同频率下,激励声压越大血管运动越强烈,振动传播产生的局部效应更持久;(3)微泡振动幅度随微血管壁杨氏模量的增加而降低,近似线性反比关系;振动频率则随血管壁杨氏模量的增加而增加;(4)结果表明,微血管尺寸越小,对微泡振动频率和幅值的限制越强烈,超声激励频率的增大会使微泡振动频率增大、幅值减小;声压对微泡和血管振动的影响则相反。此外,研究首次发现,血管壁弹性与微泡振动幅度呈近似线性正相关,说明利用微泡测定血管壁弹性是可能的。
[Abstract]:Background: to study the nonlinear acoustic response between microvessels and internal microbubbles under specific ultrasound excitation, to maximize the deposition of ultrasonic energy, to promote the development of quantitative imaging algorithms, to reveal the mechanism of damage or to evaluate the effectiveness of targeted therapy. To overcome the limitations of traditional methods for large blood vessels, it is of great significance to measure the elasticity of microvessels. Objective: to establish a model of ultrasound microbubbles in microvasculature, and to reveal ultrasound, microbubbles and blood vessels. Methods: based on finite element analysis and lumped parameter model, The three-dimensional model of ultrasonic microbubbles in microvessels was constructed and simulated on the platform of Comsol Multiphysics 3.5a. Results and conclusions: the radial motion of microbubbles is limited by the wall of the near vessels, and the moving speed is smaller than that of the axial ones, and the wall of the microbubbles is coupled with the vibration of the microbubbles. Under the same sound pressure, the increase of excitation frequency will weaken the scaling of the microvessel and stabilize faster, and at the same frequency, the larger the sound pressure, the stronger the blood vessel movement. The vibration amplitude of microbubble decreases with the increase of Young's modulus of microvascular wall, and the vibration frequency increases with the increase of Young's modulus of vascular wall. The smaller the microvessel size, the stronger the limitation on the vibration frequency and amplitude of the microbubble, and the larger the ultrasonic excitation frequency, the larger the vibration frequency and amplitude of the microbubble. The effect of sound pressure on the vibration of microbubble and blood vessel is opposite. There is an approximate linear correlation between the elasticity of vascular wall and the amplitude of vibration of microbubble, which indicates that it is possible to measure the elasticity of vascular wall by using microbubbles.
【作者单位】： 华南理工大学材料科学与工程学院生物医学工程系;
【基金】：国家自然科学基金资助项目(31371008,81171179) 广东省科技计划项目(2015A02024006)~~
【分类号】：R445.1
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本文编号：1686941