超声粒子图像测速技术评估左心室涡旋特性的初步研究

Preliminary Study of Application of the Ultrasonic Particle Image Velocimetry Technique in Evaluation of Left Ventricular Vortex Characteristics

左心室涡旋特性可被认为是心脏健康潜在的指示器,通过超声粒子图像测速技术计算心脏内涡旋特性是一个较新的研究方向,关键是要证明其具有足够的可靠性和精确性,以便用于临床应用。为此,本文构建了一个超声粒子图像测速技术系统,搭建了一个人体血液循环仿真系统,通过聚乙烯醇(PVA)制作了左心室仿体,以便在受控条件下测试超声粒子图像测速技术计算心脏内涡旋特性的可行性。系统可以对仿体进行连续成像,通过调整扫描线密度、图像宽度、图像深度等参数,最快可以实现每秒钟上千帧的成像速度。实验过程中,在液体水池中打入超声造影微泡,开启脉动泵循环多个周期,对仿体进行实验采集。通过超声粒子图像测速技术可得到心脏内血液流动的速度分布,进一步可计算出心脏内涡旋的相关参数,包括能量损失(DI)、能量波动(EF)、涡旋相对强度(RS)、涡旋的波动(W)等。结果证明所构建的系统、仿体、相关算法是可行的,可为下一步工作打好基础。

The vortex properties of left ventricles can be considered as a potential indicator for heart＇s health status. Using the ultrasonic particle image velocimetry（PIV） technique to calculate the characteristics of vortex in the heart is a relatively new research direction, and the key is to prove its adequate reliability and accuracy for clinical applications. For this purpose, a ultrasonic particle image velocimetry system was constructed to build a human blood circulation simulation system. And the polyvinyl alcohol（PVA） was used to make the left ventricular phantoms, so that the ultrasonic PIV technique could be tested in controlled conditions for the calculation of the vortex characteristics in the heart. The system achieved continuous imaging of the body, by adjusting the scanning line density, image width, image depth and other parameters, with the fastest speed of thousands of frames per second. Cardiac blood flow velocity profiles were obtained through the algorithm of acoustic PIV and further calculation of relevant parameters for the vortex in the heart, including energy loss（DI） and energy fluctuations（EF）, vortex relative strength（RS） and eddy fluctuations（W）. The results show that the constructed system, the simulated body and the related algorithms are feasible, which is the basis for the next step of work.