基于高帧率成像的血管超声弹性成像方法研究

发布时间：2018-05-18 02:42

本文选题：动脉粥样硬化斑块 + 高帧率成像　；参考：《深圳大学》2016年硕士论文

【摘要】：近年来脑血管疾病已成为我国城市和农村人口第一位的致残和死亡原因,且发病率有逐年增多的趋势,颈动脉粥样硬化(Carotid atherosclerosis,CAS)是引起缺血性脑卒中的主要原因之一。颈动脉粥样硬化斑块可分为稳定性和不稳定性斑块,不稳定性斑块中易引起急性缺血性事件的易损斑块尤其值得我们重点关注。目前超声检查是公认的评估动脉粥样硬化斑块性质的一种最便捷、有效的手段,但是常规超声对斑块的内部力学特性难以准确测量。研究表明,斑块的不同成分间力学特性有明显的差异,超声弹性成像作为从影像学来判断生物组织力学特性的技术,能提供给临床医生动脉粥样硬化斑块的力学信息,鉴别颈动脉粥样硬化斑块的易损性,预防脑卒中的发生。准静态血管超声弹性成像方法的基本原理是心脏周期性射血运动下血管内壁受管腔内血压的冲击激励而产生应变。本研究的主要目的是探索高帧率成像算法与准静态弹性成像相结合的方法在动脉粥样硬化易损斑块定征测量上的应用前景。本研究的主要内容包括:(1)通过对前沿高帧率成像的研究以及对平面波波束合成算法的研究,基于Vantage平台完成高帧率成像算法的开发,并分别实现基于时域和频域的两种波束合成算法,使B超成像帧率达到了1K以上。通过分辨率仿体成像实验,验证了两种算法的可行性,并定量比较了两种成像方法的图像质量。(2)在实验室已有工作基础上,改进了基于块匹配的相移算法,同时提出了一种新的基于先验估计的二维互相关算法,利用仿真信号对两种弹性成像算法进行了验证同时做了对比讨论和分析。(3)结合高帧率成像,将准静态弹性成像算法应用于有不同弹性分段区分的血管仿体,实验证明了该方法在区分不同硬度血管壁上的可行性。(4)与深圳市第二人民医院超声科合作,采集了动脉粥样硬化患者的相关临床实验数据,成功区分了动脉粥样硬化患者纵向切面血管壁斑块的软硬程度。
[Abstract]:In recent years, cerebrovascular disease has become the first cause of disability and death in urban and rural population in China, and the incidence of cerebral vascular disease has been increasing year by year. Carotid atherosclerosis (CASs) is one of the main causes of ischemic stroke. Carotid atherosclerotic plaque can be divided into stable plaque and unstable plaque. At present, ultrasound is recognized as the most convenient and effective method to evaluate the nature of atherosclerotic plaques, but it is difficult to accurately measure the internal mechanical properties of atherosclerotic plaques by conventional ultrasound. Studies have shown that there are significant differences in mechanical properties among different components of plaques. As a technique for judging biomechanical properties of biomechanical tissue by imaging, ultrasonic elastic imaging can provide clinicians with mechanical information of atherosclerotic plaques. Identify the vulnerability of carotid atherosclerotic plaques and prevent stroke. The basic principle of quasi static vascular ultrasound elastography is that the inner wall of blood vessels is strained by the impulse of blood pressure in the lumen under the periodic ejection motion of the heart. The main purpose of this study is to explore the application prospect of high frame rate imaging algorithm combined with quasi-static elastic imaging in the determination of atherosclerotic plaques. The main contents of this study include: (1) through the research of frontier high frame rate imaging and the research of plane wave beam synthesis algorithm, the development of high frame rate imaging algorithm based on Vantage platform is completed. Two beam-synthesizing algorithms based on time-domain and frequency-domain are implemented respectively, and the frame rate of B-ultrasound imaging is over 1K. The feasibility of the two algorithms is verified by the resolution simulation experiment, and the image quality of the two imaging methods is compared quantitatively. The phase shift algorithm based on block matching is improved on the basis of the existing work in the laboratory. At the same time, a new two-dimensional cross-correlation algorithm based on prior estimation is proposed. The simulation signals are used to verify the two elastic imaging algorithms. The quasi-static elastic imaging algorithm is applied to vascular replicas with different elastic segmental differentiation. The feasibility of this method in distinguishing vascular walls with different hardness is proved by experiments. The method cooperates with the ultrasonic department of the second people's Hospital of Shenzhen City. The clinical data of atherosclerotic patients were collected, and the degree of soft and hard plaques on the longitudinal section of atherosclerosis was distinguished successfully.
【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：R445.1;R543.4

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