A NONINVASIVE METHOD TO ESTIMATE WALL SHEAR RATE USING ULTRASOUND
A NONINVASIVE METHOD TO ESTIMATE WALL SHEAR RATE USING ULTRASOUND
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DOI：
10.1016/s0301-5629(94)00111-1
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发表时间：
1995-01-01
影响因子：
2.9
通讯作者：
RENEMAN, RS
中科院分区：
文献类型：
--
作者：
BRANDS, PJ;HOEKS, APG;RENEMAN, RS
由流动的血液施加的壁剪切应力（血液粘度X壁剪切速率）和血压是作用在血管壁上的主要机械力。在研究血管疾病的发展时，壁剪切应力的准确测量是重要的，因为高和低的壁剪切应力都被认为是导致血管壁异常的因素。此外，体外研究表明，内皮细胞，在下面的动脉壁的功能中发挥关键作用，经历了各种结构和功能的变化，以响应施加的剪切应力。然而，实际上没有关于壁剪切应力对体内动脉壁的影响的知识，因为难以测量该应力的大小和时间变化。本文提出的方法来测量的主要动脉中的时间依赖性的壁剪切率是基于通过超声确定的速度分布的评价，使用离线信号处理。脉冲超声非常适合这种应用，因为它是无创的。在射频（RF）域中执行的处理由平均频率估计器和自适应血管壁滤波器组成。在一项初步研究中（5名健康志愿者的颈动脉中进行了30次测量），我们研究了我们的方法的可重复性，以估计壁剪切率，与测量血管中部血液流速的可重复性相比。血液流速估计的变异系数为9%，壁剪切速率估计的变异系数为5%。
Wall shear stress (blood viscosity x wall shear rate), imposed by the flowing blood, and blood pressure are the main mechanical forces acting on a blood vessel wall. Accurate measurement of wall shear stress is important when investigating the development of vascular disease, since both high and low wall shear stresses have been cited as factors leading to vessel wall anomalies. Furthermore, in vitro studies have shown that endothelial cells, which play a key role in the function of the underlying arterial wall, undergo a variety of structural and functional changes in response to imposed shear stress. However, there is practically no knowledge about the influence of wall shear stress on the arterial wall in vivo because of the difficulty in measuring this stress in terms of magnitude and time variation. The method presented in this article to measure the time-dependent wall shear rate in the main arteries is based on the evaluation of velocity profiles determined by means of ultrasound, using off-line signal processing. Pulsed ultrasound is well suited for this application since it is noninvasive. The processing performed in the radio-frequency (RF) domain consists of a mean frequency estimator preceded by an adaptive vessel wall filter. In a pilot study (30 measurements in the carotid artery of five healthy volunteers) we investigated the reproducibility of our method to estimate wall shear rate as compared with the reproducibility of the measurement of blood how velocity in the middle of the vessel. The coefficient of variation was on the order of 9% for blood how velocity estimation, and for wall shear rate estimation on the order of 5%.