Transcranial Doppler (TCD) is a common technique used for studying haemodynamics of intracranial vessels. The traditional TCD has some disadvantages, such as difficulties in positioning the blood vessels and detecting the embolus in human's brain. To overcome these deficiencies, a power motion-mode TCD measurement system is designed by combining different modules, such as field-programmable gate array, USB chips and processed data on personal computer. The digital circuit module centred on field-programmable gate array was applied for designing the system state machine. Meanwhile, high-speed AD simultaneous sampling chip and ping-pong working mode of dual FIFO were used to assure a real-time performance. The data transmission between hardware and personal computer was realized by high-speed USB. The software module combined with power motion-mode imaging technique, short time Fourier transform and pseudo-color image processing to monitor the whole state of blood vessels in the transmitting ditrection of ultrasonic beams, which can easily locate blood vessels and provide the doctors with more information of the ultrasonic spectrum.%经颅多普勒(TCD)是研究颅内大血管中血流动力学的常用技术,但传统TCD中依然存在着对大脑血管定位困难和对微栓子检测不确定等缺点.为了克服这些弊端,本研究设计了一种功率M模式TCD测量系统.该系统通过FPGA设计、USB固件驱动以及PC数据后处理等模块共同实现.数字电路模块以FPGA为核心进行状态机设计,并采用高速AD采样和双FIFO乒乓工作模式来确保良好的实时性;硬件电路部分和PC之间的数据传输依靠高速USB实现;软件模块结合功率M模式多普勒成像技术、短时傅里叶变换和伪彩色图像处理,对超声波束发射方向上整体深度的血流状态进行监测,方便定位血管深度,并为临床医生提供选通深度的声谱图信息.
展开▼
