基于超高速超声与剪切波成像的局部血管弹性无创测量方法研究

Cardiovascular disease is the No. 1 killer in China. Noninvasive measurement of regional vascular elasticity is of great value in the clinic. Shear wave imaging is an important quantitative elasticity imaging method, and its applications in the measurement of regional arterial elasticity have attracted researchers’ attention. Vessel is an anisotropic tissue. However, most of the current studies on shear wave imaging mainly focus on the longitudinal section of vessels, and thus cannot completely evaluate the mechanical properties of vessels. This project will achieve ultrafast ultrasound imaging through plane wave transmit, parallel data acquisition and beamforming, so as to increase the precision of shear wave motion estimation. The vessel will be scanned in both longitudinal and transverse sections, the shear wave motion estimation methods for different sections will be investigated, the corresponding shear wave dispersion curves will be obtained, and the vascular elasticity in different directions will be quantitatively measured, so as to investigate the mechanical properties of vessels more completely. In addition, the project will investigate the relationship between shear wave dispersion curves and blood pressure, and will propose a method for noninvasive measurement of local blood pressure according to such relationship. This project will perform computer simulations, vessel phantom experiments and in vivo experiments in order to validate the reliability of the proposed method. This project will obtain simultaneous, noninvasive and quantitative measurement of the regional vascular elasticity in different directions and local blood pressure, and thus can evaluate the function of vessels more completely, which could be used for the diagnosis and risk assessment of cardiovascular disease.

心血管疾病是我国头号杀手，局部血管弹性的无创测量对于心血管疾病诊断具有重要的临床价值。超声剪切波成像是一种重要的定量弹性成像方法，其在血管弹性测量的应用引起研究人员的关注。血管是一种各向异性的组织，但是，目前的大部分剪切波成像研究集中在血管纵向切面上，不能全面评价血管的力学特性。本项目通过基于平面波发射、并行数据采集和波束合成，实现超高速成像，提高剪切波位移估计的精度；分别对血管的纵向和横向切面进行扫描，研究不同切面的剪切波位移估计方法，得到相应的剪切波频散曲线，并获得不同方向的血管弹性定量测量, 从而更全面地评价血管的力学特性；进一步，通过研究剪切波频散曲线和血压的关系，提出局部血压的无创测量方法。本项目将通过计算机仿真、血管仿体实验和在体实验，验证方法的可靠性。本项目将同时获得不同方向的局部血管弹性和血压的无创、定量测量，从而更全面地评价血管的功能，可望用于心血管疾病的诊断与风险预测。

局部血管弹性的无创测量对于心血管疾病诊断具有重要的临床价值。超声剪切波成像是一种重要的定量弹性成像方法，其在血管弹性测量的应用引起研究人员的关注。血管是一种各向异性的组织，但是，目前的大部分剪切波成像研究集中在血管纵向切面上，不能全面评价血管的力学特性。此外剪切波弹性成像的计算速度、横向位移估计的质量都影响了该技术的临床应用。为了解决这些问题，本项目通过基于平面波发射、并行数据采集和波束合成，实现超高速成像，提高剪切波位移估计的精度；研究剪切波弹性成像方法，提出基于SVD滤波的剪切波弹性成像方法，不仅提升了成像速度，还得到比较好的图像质量；通过参数优化研究，得到最佳的角度复合数量、角度偏转大小和帧频设置；通过编码激励方法研究，得到更好的横向位移估计效果；通过分别对血管的纵向和横向切面进行扫描，获得不同方向的血管弹性定量测量, 更全面地评价血管的力学特性；进一步，通过基于射频数据进行了定量超声研究，为弹性成像提供了新参数；并通过计算机仿真、仿体实验和在体实验，验证方法的可靠性。本项目通过开发多种方法得到更好的弹性成像效果，同时获得不同方向的局部血管弹性和血压的无创、定量测量，从而更全面地评价血管的功能，可望用于心血管疾病的诊断与风险预测。