高频超声在浅表器官低速血流成像中的实验研究

In ultrasonic imaging, due to the echo of the blood is very weak, the traditional method of B-mode blood flow imaging is using coded excitation techniques to improve the back-scattering signals of red blood cells as the prerequisite. Then the application is in the low frequency range and limits the resolution of blood flow. What more, in the clinical diagnosis of diseases, to determine the direction of blood flow, the Doppler ultrasound should be scanned with B-mode blood flow imaging. This project is to research on the back-scattering of red blood cells for high frequency ultrasound in which the frequency is between 20 MHz to 50 MHz, and especially when the ultrasonic transmitting frequency is greater than 34 MHz. This research will establish a blood flow simulation model, and construct a high resolution experiment device. According to the characteristics of the blood flow echo signals, this research will explore the relationship between B-mode blood flow imaging and ultrasonic transmitting frequency, the blood flow velocity, scanning depth and mode. this project will form a new B-mode blood flow imaging method with high resolution, lay theoretical basis for the low velocity blood flow imaging in superficial organs.

在超声成像中，由于血液的回声非常微弱，传统的灰阶血流成像方式是以编码发射技术提高红细胞的背向散射信号为前提的，因此只能应用于较低的频率范围内，限制了血流分辨率的提高；而且在临床疾病的诊断中，灰阶血流成像需要配合多普勒超声扫查才能确定血流方向，为疾病的诊断提供可靠依据。本项目的重点是研究血液中红细胞对20 MHZ至50 MHz的高频超声的背向散射特性，重点是研究当超声发射频率大于34 MHz时红细胞的散射规律。研究中将建立血流仿真实验模型，构建高分辨率实验装置，根据血流回声信号的特点，探索灰阶血流成像与超声发射频率、血流速度、探测深度和扫查方式等的关系，可望形成一种高分辨率的灰阶血流成像方法，为浅表器官低速血流成像奠定实验基础。