基于高分辨超声成像平台的无创血管力学及动力学特性分析研究报告

万明习　宗瑜瑾　万锦锦

摘要：本研究提出了一种可同时无创测量颈动脉壁力学特性、血管壁剪切率的变化以及脉搏波在局部短距离血管片段上传播速度的超声定量成像和评价方法。为了提高超声成像的分辨性能，同时补偿由于入射角度不同造成的血管侧壁灰度的非均匀性，在应变估计之前首先对超声图像进行了高分辨图像重建与灰度非均匀性的校正。在相同的成像平面下，保持声束与血流的夹角呈90°，血流速度与剪切率沿管径的分布可由沿血管直径方向采集的若干个位置处的横向多普勒信号重建得到。最后，使用超快速平面波成像技术结合射频互相关算法可获取沿38mm血管片段的膨胀波群及脉搏波传播速度。目前临床动脉粥样硬化病人的在体实验已证实了该方法在斑块早期诊断中的有效性，因此本研究提出的超声定量成像和评价方法有望成为一种颈动脉粥样硬化斑块普查的新手段。

关键词：颈动脉粥样硬化；径向应变；血管壁剪切率；脉搏波波速；平面波超声成像

Abstract：In this work， a combined strategy for noninvasively measuring the carotid artery wall mechanics， the near wall shear rate （WSR） and the local pulse wave velocity （PWV） is presented. First， a combination of super-resolution reconstruction with the circumferential non-uniform correction for the artery wall is introduced before strain estimation to conquer the spatial limitation of ultrasound video images. Under the same imaging plane， with a beam-to-flow angle of 90°， the blood velocity and shear rate distributions along the artery diameter can be reconstructed from the transverse Doppler spectra. Finally， the artery distension waveforms and local PWV of a 38 mm-length segment are calculated by the cross-correlation method using plane wave ultrasound with a frame rate of 2000Hz. The clinical results over atherosclerosis patients demonstrate the feasibility of these methods. In conclusion， the current ultrasound method can provide additional valuable results as a supplement to the current routine ultrasound examination for carotid atherosclerosis， thereby having significant potential as a feasible screening method for atherosclerosis diagnosis in the future.

Keywords：Carotid atherosclerosis； radial strain； wall shear rate； pulse wave velocity； plane wave ultrasound imaging