基于高分辨超聲成像平臺的無創血管力學及動力學特性分析研究報告

萬明習　宗瑜瑾　萬錦錦

摘要：本研究提出了一種可同時無創測量頸動脈壁力學特性、血管壁剪切率的變化以及脈搏波在局部短距離血管片段上傳播速度的超聲定量成像和評價方法。為了提高超聲成像的分辨性能，同時補償由于入射角度不同造成的血管側壁灰度的非均勻性，在應變估計之前首先對超聲圖像進行了高分辨圖像重建與灰度非均勻性的校正。在相同的成像平面下，保持聲束與血流的夾角呈90°，血流速度與剪切率沿管徑的分布可由沿血管直徑方向采集的若干個位置處的橫向多普勒信號重建得到。最后，使用超快速平面波成像技術結合射頻互相關算法可獲取沿38mm血管片段的膨脹波群及脈搏波傳播速度。目前臨床動脈粥樣硬化病人的在體實驗已證實了該方法在斑塊早期診斷中的有效性，因此本研究提出的超聲定量成像和評價方法有望成為一種頸動脈粥樣硬化斑塊普查的新手段。

關鍵詞：頸動脈粥樣硬化；徑向應變；血管壁剪切率；脈搏波波速；平面波超聲成像

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