为了精确监测脑血管手术中术野范围内目标血管的流速及流量, 研究了一种基于激光散斑衬比成像(Laser Speckle Contrast Imaging, LSCI)技术的脑血流分析方法, 来确认血管吻合后血流的流通及脑部血流灌注情况。首先, 搭建LSCI系统采集散斑图像, 对它进行改进的时间衬比分析和伪彩色处理, 得到血流速度图像来监测流速变化。其次, 手动选取感兴趣区域的基准点截取感兴趣区域, 对感兴趣区域图像预处理后利用改进的Canny算法提取血管边缘线并计算血管管径。最后, 通过动物实验验证LSCI系统血流速度变化监测和血管管径测量功能的可靠性。实验结果显示: 改进的Canny算法将血管管径测量的相对误差降低到5.1%。基于LSCI技术的脑血流分析方法可监测血流速度变化, 并测量得到血管的有效流通直径, 结合激光多普勒血流仪可以实现术中血流流速及流量的精确监测。

During cerebrovascular surgery, it is necessary to monitor the flow velocity and the flow in the target blood vessel. In this study, a method of cerebral blood flow analysis based on laser speckle contrast imaging (LSCI) technology was investigated to evaluate the blood flow conditions and cerebral blood flow perfusion after vascular anastomosis. First, the LSCI system was developed to acquire speckle images, and the blood flow velocity image was captured through improved time contrast analysis and pseudocolor processing to monitor the change in flow velocity. Next, the reference points of the region of interest (ROI) were manually selected to intercept the ROI. After the image preprocessing of the ROI was carried out, the improved Canny algorithm was used to extract the edge line of the blood vessel and calculate the blood vessel diameter. Finally, reliability for blood-flow velocity-change monitoring and blood-vessel diameter measurement functions of the LSCI system were verified through animal experiments. The experimental results showed that the improved Canny algorithm decreased the relative error of the vessel diameter to 5.1%. The cerebral blood flow analysis method based on LSCI technology is suitable for monitoring variations in blood flow velocity and measuring the effective flow diameter of blood vessels. When the proposed method is combined with a laser Doppler blood flow meter, blood flow velocity and flow during surgery can be monitored accurately.