Mokhtari-Dizaji Manijhe, Montazeri Mahmood, Saberi Hajir
Department of Medical Physics, Tarbiat Modares University, Tehran, Iran.
Ultrasound Med Biol. 2006 Oct;32(10):1493-8. doi: 10.1016/j.ultrasmedbio.2006.05.023.
Doppler ultrasound technique is now recognized as the best noninvasive screening test for carotid artery stenosis. Ultrasound does not calculate directly the degree of arterial narrowing, but relies on extrapolating the changes in blood flow parameters to an anatomical stenosis. This paper deals with the estimation of the stiffness indices of mild and severe stenosis of common carotid artery by motion estimation algorithm, focusing on their changes with the progression of atherosclerosis. 145 men with the mean age of 55 +/- 12 y who were healthy or had mild stenosis or severe stenosis were studied. For each ultrasound examination, matching longitudinal views of the common carotid artery were located, the frames were grabbed and processed with motion estimation algorithm and then diameter, cross-section changes and intima-media thickness of the right common carotid artery were estimated. The blood pressure was recorded in the right brachial artery using a semiautomatic device. The arterial diameter and cross-section changes and intima-media thickness were used together with the blood pressure measurements to estimate standard arterial stiffness indices. Relative diameter changes in carotid arteries with mild and severe stenosis were decreased by 22% to 48%, respectively, compared with healthy carotid artery. Systolic blood pressure in mild stenosis was approximately 4.4% lower and in severe stenosis was 2.0% higher compared with the healthy carotid. The stiffness indices were significantly different in the group of patients with severe stenosis (p-value < 0.05) compared with the healthy and mild stenosis subjects. It is concluded that, regarding the influence of atherosclerosis on the stiffness indices of right common carotid artery, we can differentiate mild and severe stenosis in carotid artery, through processing the sequential color Doppler ultrasound images by optical flow tracking algorithm.
多普勒超声技术现已被公认为是检测颈动脉狭窄的最佳无创筛查方法。超声不能直接计算动脉狭窄程度，而是依靠将血流参数的变化外推至解剖学上的狭窄情况。本文通过运动估计算法来评估颈总动脉轻度和重度狭窄的硬度指数，重点关注其随动脉粥样硬化进展的变化。研究对象为145名平均年龄55±12岁的男性，他们身体健康或患有轻度或重度狭窄。每次超声检查时，定位颈总动脉的匹配纵向视图，抓取图像并用运动估计算法进行处理，然后估算右侧颈总动脉的直径、横截面积变化和内膜中层厚度。使用半自动设备记录右侧肱动脉的血压。将动脉直径、横截面积变化和内膜中层厚度与血压测量值一起用于估算标准动脉硬度指数。与健康颈动脉相比，轻度和重度狭窄的颈动脉相对直径变化分别降低了22%至48%。与健康颈动脉相比，轻度狭窄时收缩压约低4.4%，重度狭窄时高2.0%。与健康和轻度狭窄受试者相比，重度狭窄患者组的硬度指数有显著差异（p值<0.05）。研究得出结论，关于动脉粥样硬化对右侧颈总动脉硬度指数的影响，通过光流跟踪算法处理连续彩色多普勒超声图像，我们可以区分颈动脉的轻度和重度狭窄。
