Microscopic visualization of blood multihpase flow using fluorescent tracers

流动可视化可用于对流速的定量分析以及对流型的理解。在每个问题中都有必要开发相应的技术来可视化流程。本项目的目的是发展一种新的血流可视化技术，从而分析不同器官的多相流现象。我们使用荧光示踪剂进行流动可视化，并开发了一种配备硅强化视频（SIT）摄像机的荧光视频显微镜。在这个实验系统中，悬浮在血液中的荧光粒子的运动可以在视频监视器上清晰而独立地观察到。利用视频监视器在两个窗口测量粒子的光强，我们可以评估它们在单个容器中的流速。还可以测量血管横截面上红细胞的分布。该方法的优点是由于荧光示踪剂的高质量图像，可以测量大范围的速度。基于荧光示踪法，我们研究了血细胞悬浮液在玻璃管或脑血管分叉中的稳定流动。通过反复录像，我们仔细检查了流型和速度分布。此外，我们还对大鼠脑动脉分叉和猫大脑皮层微血管网络的血流进行了体内显像。我们展示了多相流现象，如无细胞等离子体流和红细胞聚集流。

Flow visualation is avaliable for quantative analysis of the flow velocityas well as understanding of flow pattern. It is necessary in each prob I em to dev i se the correspond ing technique tovisualize flow. The purpose of this pro-ject is to develop a new technique for visualizing blood flow, and then to analyze multiphase flow phenomena in various organs.We used fluorescent tracers for flow visualization, and developed a fluorescence video-microscope equipped with a silicon intensified video(SIT)camera. In this experimental system, motions of fluorescent particles suspended in blood could be observed clearly and independently on the video-mionitor. Using the light intensity of particles measured at two windows on t he video-monitor, we could evaluated their flow velocities in single vessels. It was also possible to measure the distribution of red cell over a cross-section of the vessel. The present method has an advantage that a large range of velocity can be measured due to the high-quality image of fluorescent tracers.Based on the fluorescent tracer method, we investigated steady flows of blood cell suspensions in glass tubes or cerebrovascular bifurcation. By repeated video-recordings, we made close examination of the flow pattern and velocity profile. Moreover, we made in vivo flow vis ualiation of blood flow in cerebral arterial bifurcations of rats and in microvascular networks of cats's cerebral cortex. We demonstrated multiphase flow phenomena such as cell-free plasma flow and red cell aggregation flow.