Measurement of Blood Flow Velocity in Cerebral Microvessels by a Fiber-Optic Laser-Doppler Anemometer Microscope

光纤激光多普勒风速计显微镜测量脑微血管血流速度

基本信息

批准号：
06671432
负责人：
SEKI Junji
金额：
$ 1.28万
依托单位：
National Cardiovasular Center Reseauch Institute
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

This research project was aimed to establish the applicability of our developed fiber-optic laser-Doppler anemometer microscope (FLDAM) to the measurement of red cell velocity in the cerebral pial microvessels and was also aimed to analyze the blood flow dynamics under the increased intracranial pressures.A closed cranial window was implanted on one side of the parietal region of rats to observe the brain pial microcirculation. The red cell velocity in single pial microvessels with diameter range from 10 to 230 mum was successfully measured by the FLDAM.The red cell velocity in arterioles showed regular pulsation synchronous with the heart beats with amplitude up to 46 % of the mean velocity, while the velocity in venules only showed random fluctuations with small amplitude. The amplitude of velocity pulsation was defined as the half of the difference betweenthe maximum and minimum of the ensemble average velocity. The temporal mean velocity in the arterioles increased with increasing … More diameter. It was 3.5 and 14 mm/s for the arteriole with 10 and 50 mum in diameter, respectively, on an average. The time lag of the velocity in the arteriole relative to the femoral arterial pressure increased with the distance along the vessel from upstream to downstream, which indicates the propagation of flow pulse along the arteriole. The propagation velocity of flow pulse was determined for several pial arterioles. It ranged between 10 and 115 cm/s.Effects of intracranial pressure (ICP) on the pial microcirculation were studied by changing the internal pressure of the closed cranial window implanted in the rats. The average diameter of venules decreased monotonically from 1.1 to 0.78 as the ICP increased from 0 to 50 mmHg, where the diameter is normalized by the diameter at ICP=5mmHg. On the other hand, the temporal mean velocity in venules increased monotonically from 0.85 to 1.91. As a result, the volume flow rate in venules did not change significantly with ICP.The changes of arterioles with ICP were small compared with those of venules. The amplitude of velocity pulsation in arterioles showed stepwise increase with ICP at a certain value of ICP,ICP_<cr'> which depended on the location of the vessel. ICP_<cr> increased with increasing vessel diameter and decreased from upstream to downstream along an arteriole, suggesting that ICP_<cr> represents the intravascular pressure of the arteriole at a certain phase of pulsation. Less

该研究项目旨在建立我们开发的光纤激光多普勒风速计显微镜（FLDAM）在测量脑软膜微血管中红细胞速度的适用性，并旨在分析颅内压升高下的血流动力学.在大鼠顶叶一侧植入封闭式颅窗，观察脑软膜微循环，直径为10μm的单个软膜微血管的红细胞速度。 FLDAM成功测量到230μm。小动脉中的红细胞速度呈现与心脏搏动同步的规则搏动，幅度高达平均速度的46％，而小静脉中的速度仅呈现随机波动，速度幅度较小。脉动被定义为整体平均速度的最大值和最小值之差的一半，小动脉的时间平均速度随着直径的增加而增加，为 3.5。直径为10μm和50μm的小动脉平均分别为14mm/s。小动脉中的速度相对于股动脉压力的时滞随着血管从上游到下游的距离增加而增加。表示流脉冲沿小动脉的传播。确定了几个软脑膜小动脉的流脉冲的传播速度，其范围在 10 到 115 之间。 cm/s。通过改变大鼠闭合颅窗植入直径的内压来研究颅内压（ICP）对软脑膜微循环的影响。随着ICP从0增加到0.78，微静脉的平均值单调地从1.1增加到0.78。 50 mmHg，其中直径通过 ICP=5mmHg 时的直径标准化。另一方面，小静脉中的时间平均速度增加。从 0.85 到 1.91 单调变化，小动脉中的体积流量随 ICP 的变化不显着。与小静脉相比，小动脉中的速度脉动幅度随 ICP 呈逐步增加。 ICP,ICP_<cr'> 的某个值取决于容器的位置，ICP_<cr> 随着容器直径的增加而增加，并且随着容器直径的增加而减小。沿着小动脉从上游到下游，表明 ICP_<cr> 代表小动脉在某个搏动阶段的血管内压力。