基于漫射光相关谱和红细胞运动规律的组织血流灌注研究

Study on Tissue Blood Perfusion Based on Diffuse Correlation Spectroscopy and Red Blood Cell Movement Patterns

目的根据红细胞运动原理建立红细胞运动与组织灌注间的联系,探究漫射光相关谱(Diffuse Correlation Spectroscopy,DCS)测量血流指数的物理和生理意义。方法结合朗之万方程及流体动力学来研究红细胞的运动及受力情况,并根据其在组织内的扩散规律来获得组织灌注特征。在计算机仿真中,利用COMSOL有限元软件搭建微血管网络结构模型,根据以上的动力学规律获得粒子运动的均方位移与体积增量间的联系。结果经过理论分析及仿真验证,发现微血管中红细胞的运动不是自发的热布朗运动,而是受流体动力学主导的主动扩散运动,且粒子的均方位移与体积增量呈正向非线性关系。结论DCS测量的血流指数虽然与传统意义上的生理血流单位不同,但该血流指数可以表征深层组织微血管的血流状态,并作为衡量组织灌注能力的指标。

Objective To establish a link between red blood cell motion and tissue perfusion based on the principle of red blood cells motion,and to explore the physical and physiological significance of measuring blood flow index using diffuse correlation spectroscopy(DCS).Methods Langevin equation and fluid dynamics were combined to study the motion and stress of red blood cell,and obtained tissue perfusion characteristics based on their diffusion pattern within the tissue.In the computer simulation,we used COMSOL finite element software to build a structural model of the microvascular network and obtained the connection between the mean square displacement and volume increment of particle motion according to the above kinetic law.Results Through theoretical analysis and simulation verification showed that the motion of red blood cells in micro vessels was not a spontaneous thermal Brownian motion,but an active diffusion motion dominated by fluid dynamics,and the mean square displacement of particles was positively and nonlinearly with the volume increment.Conclusion Although the blood flow index measured by DCS is different from the physiological blood flow unit in the traditional sense,it can characterize the blood flow status of micro vessels in deep tissue and be used as an indicator to measure tissue perfusion capacity.