颈动脉血管壁面剪切率超声检测关键技术研究

Wall shear rate (WSR) is defined as the radial velocity gradient in the radial direction for the axial blood blow close to the arterial walls. The latest pathological studies expose that as the gene expression and regulation mechanism of endothelial cells, lower and oscillatory WSR are essential to the foundation and development of atherosclerosis. It is a hotpot to acquire the WSR for prediction and quantification of atherosclerosis disease by using ultrasound technique. However, there are two difficulties for directly detection of the WSR: 1) effectively reject the disturbance from the pulsatile moving vessel wall; 2) improve the detection precision of the velocity profile of the blood flow close to the vessel wall. In present project, based on the nonlinear adaptive signal processing theory, we propose an ideal of variable or adaptive regulation for time intervals of pulse wave shooting during the ultrasonic scanning, and then will study the high performance separation approaches for the signals echoed from pulsatile blood and moving vessel walls to accurately extract the slow blood flow close to the vessel wall. We will study the approaches for autocorrelation estimation of blood flow velocity profile to accurately detection the velocity profile of the blood flow close to the vessel wall. The results could be helpful to realize the direct WSR detection in clinic, and be significant for providing evidences and methods for accurate prediction of atherosclerosis diseases.

血管腔内壁处轴向血流速度的径向变化率定义为血管壁面剪切率(Wall Shear Rate, WSR)。最新病理学研究结果表明，作为一种管壁内皮细胞基因表达调节机制，较低或震荡变化的WSR是动脉粥样硬化病变的重要诱因。应用超声技术获取WSR预测动脉粥样硬化病变是目前国内外的研究热点。然而使用超声直接检测WSR存在以下两个难点：1）有效抑制脉动血管壁及周围组织的低频高强度超声信号干扰；2）提高血管内壁周围轴向血流速度剖面的估计精度。项目拟基于非线性自适应信号处理理论，提出线阵超声扫描过程中可变或自适应调整脉冲发射间隔时间的思想，研究高性能搏动管壁与血流超声反射混合信号的分离方法，准确提取靠近管腔内壁周围的缓慢血流信号；研究自适应自相关血流速度剖面估计方法，准确检测管腔内壁周围慢速血流速度剖面；研究结果将有助于实现WSR的临床超声直接检测，对预测脑血管疾病的发生具有重要意义。

按照计划任务书规定的内容，项目拟基于非线性自适应信号处理理论，提出线阵超声扫描过程中可变或自适应调整脉冲发射间隔时间的思想，研究高性能搏动管壁与血流超声反射混合信号的分离方法，准确提取靠近管腔内壁周围的缓慢血流信号；研究自适应自相关血流速度剖面估计方法，准确检测管腔内壁周围慢速血流速度剖面；研究结果将有助于实现WSR的临床超声直接检测，为深入分析研究粥样硬化斑块病变及其稳定性提供可靠手段，对预测脑血管疾病的发生具有重要意义。预期在国内外核心刊物上发表高质量的10篇期刊论文和3-4篇会议论文；获2项发明专利；培养8-10名硕士研究生，2-3名博士研究生。.按照计划书的要求，课题组首先进行了资料收集、整理，消化有关的资料，写出了综述文章；开展了颈动脉超声计算机仿真建模，颈动脉B超估计血管壁搏动位移的干扰抑制，狭窄血管中血流速度与多普勒功率谱的对应关系研究。提出了一种基于伽马分布组织散射点模型的三维颈动脉三层膜动态超声模型；提出了可变或自适应发射间隔射频线血流速度剖面估计、基于超声相干平面波复合成像血流速度测量及超声回波基谐波信号的自适应分离。研究结果有助于提高对心脑血管硬化发生的认识，开发对这类疾病高危人群的筛选方法及对病情早期诊断、发展及治疗效果监测的有效、客观手段；为相关疾病高危人群风险预测和防治提供理论依据及实用的检测方法。.项目发表期刊论文14篇（通讯作者），其中SCI检索8篇(中科院二区2篇，三区4篇)，EI检索6篇，会议论文11篇（EI/ISTP检索，通讯作者）；主要成果发表在 “IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control,”，“Computer Methods and Programs in Biomedicine”、“Ultrasonic Imaging”“Computers in Biology and Medicine”，“Medical Physics”“电子学报”、“声学学报”、“电子信息学报”、“系统仿真学报”等国内外核心刊物上；申报发明专利8项（美国发明专利2项），获5项授权；培养毕业博士生4人，硕士生13人。达到了预期的目标，完成或超额完成各项指标。