Department of Electronics and Telecommunications, Università degli Studi di Firenze, Firenze, Italy.
Ultrasound Med Biol. 2011 Oct;37(10):1561-70. doi: 10.1016/j.ultrasmedbio.2011.06.001. Epub 2011 Aug 6.
In flow-mediated dilation (FMD) studies, brachial artery diameter changes due to reactive hyperaemia are typically measured through manual or automatic analysis of high resolution B-mode images while the stimulus of diameter change, i.e., the flow change, is qualitatively estimated by measuring the mean velocity in the vessel and assuming a parabolic velocity profile. This article describes an experimental approach to simultaneously measure the wall shear rate (WSR) and the diameter variations, through multigate spectral Doppler and B-mode image processing, respectively. By using an ultrasound advanced open platform (ULA-OP), experimental results from the brachial arteries of 15 presumed healthy volunteers have been obtained. The mean increments during reflow against baseline were 105% ± 22% for the peak WSR and 8% ± 3% for the FMD. The mean time interval between the WSR peak and the beginning of plateau of diameter waveform was 38 ± 8 s. The results confirm that in young healthy subjects the postischemic vasodilation of brachial artery is largely correlated to the WSR increase.
在血流介导的扩张（FMD）研究中，肱动脉直径的变化是由于反应性充血引起的，通常通过手动或自动分析高分辨率 B 型图像来测量，而直径变化的刺激，即流量变化，则通过测量血管中的平均速度并假设抛物线速度分布来定性估计。本文描述了一种通过多门频谱多普勒和 B 型图像处理分别测量壁面剪切率（WSR）和直径变化的实验方法。通过使用超声高级开放式平台（ULA-OP），从 15 名假定健康志愿者的肱动脉获得了实验结果。再灌注期间相对于基线的平均增量为峰值 WSR 的 105%±22%，FMD 的 8%±3%。WSR 峰值和直径波形平台开始之间的平均时间间隔为 38±8 s。结果证实，在年轻健康受试者中，肱动脉的缺血后血管扩张与 WSR 增加密切相关。
