血管壁周向应力和血流剪切应力相位角的高分辨超声实验研究

Cardiovascular disease (CVD) is the leading cause of death, thus new methods are urgent to be developed for early diagnosis of CVD. Wall shear stress (WSS) and circumferential stress (CS) are greatly out-of-phase or asynchronous at sites that are prone to atherosclerosis and intimal hyperplasia. The angle between WSS and CS was designated as stress phase angle (SPA). SPA not only modulates cardiovascular function, but also is a powerful criterion for early diagnosis of CVD. However, it is still short of a kind of appropriate method for quantitative measurement of SPA. Thus, this project proposes a high-resolution ultrasound imaging method to accurately measure SPA, researching the change of SPA with vascular geometry and elasticity. Our research can be detailed as: Firstly, the calculation method about SPA and the effect of vascular morphology and elasticity on SPA are studied; Secondly, a high-resolution ultrasound imaging method is proposed to simultaneous accurate obtain the curve about the change of CS and WSS with the cardiac cycle, measuring SPA; Thirdly, flow and elastic vessel phantoms are prepared, and a fluid circulation system is constructed, making the vessel phantom undergo pulsatile diastole and systole like real human vessel; Fourthly, the role of SPA in the detection and localization of vascular lesions is researched by in vitro and in vivo experiments using a high-resolution ultrasound imaging system. It can be anticipated that the accomplishment of this project can provide a new basis for the early diagnosis and prediction of cardiovascular disease.

心血管疾病已成为人类死亡病因最高的"头号杀手"，亟需发展新型早期诊断方法。研究表明，血流剪切应力和血管壁周向应力在动脉粥样硬化和内膜增生易发区域存在相位差，该相位差称之为应力相位角。应力相位角不仅影响血管功能调控，而且可作为心血管疾病早期诊断的有力判据。鉴于目前尚无针对应力相位角定量测量的方法，本项目旨在通过高分辨率超声成像方法精确测量应力相位角，研究血管几何形状和血管壁弹性改变时应力相位角的演变规律。具体包括：1）研究应力相位角计算方法，及血管形态、血管壁弹性等参数对应力相位角的影响；2）研究高分辨率超声成像方法同步精确获得血管壁周向应力和血流剪切应力随心动周期变化的波形图，测量应力相位角；3）制备血液和血管仿体，构建仿真血液循环系统；4）利用高频超声成像系统开展体外管流和活体动物实验，研究应力相位角在血管病变的检测和定位中的作用。本项目的实施可为心血管疾病的早期诊断和预测提供新的依据。

心血管疾病已成为人类死亡病因最高的“头号杀手”，亟需发展新型早期诊断方法。研究表明，血流剪切应力和血管壁周向应力在动脉粥样硬化和内膜增生易发区域存在相位差，该相位差称之为应力相位角。应力相位角不仅影响血管功能调控，而且可作为心血管疾病早期诊断的有力判据。鉴于目前尚无针对应力相位角定量测量的方法，本项目通过高分辨率超声成像方法精确测量应力相位角，研究血管几何形状和血管壁弹性改变时应力相位角的演变规律。研究结果表明：1）弹性模量越大，弹性越差的血管测量得到的应力相位角负值越大，更容易出现动脉粥样硬化。2）颈内动脉处的应力相位角负值最大，根据剪切力与动脉粥样硬化的关系可以推断出，应力相位角负值越大的位置越易出现动脉粥样硬化。由此可见，本项目的实施可为心血管疾病的早期诊断和预测提供新的依据。

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