Hemodynamic Model Based On Diffuse-related Spectral Analysis

Blood flow measurement of human tissue microvessels is essential for the diagnosis and treatment of many diseases.Near-infrared diffuse correlation spectroscopy(NIR-DCS)is a new technique of tissue blood flow measurement based on the movement of red blood cells developed in recent years.It has received more and more attention because it has the advantages of non-invasive,real-time and continuous measurement.At present,neither the random ballistic model nor the Brownian motion model suitable for DCS technology can completely explain the movement state of red blood cells in a complex vascular network,which affects the accuracy of DCS blood flow measurement.In view of this technical limitation,this paper carried out finite element simulation of red blood cell movement and liquid phantom measurement experiment and the purpose is to establish a hemodynamic model that conforms to the characteristics of microvessel structure.The innovative work of this article includes:(1)In view of the limitation that the current random ballistic model or Brownian motion model does not fully reflect the network structure characteristics of the microvascular system,this paper establishes a hybrid model combining the two models,which can more fully reflect the movement feature of red blood cells in the microvascular system.(2)A computer simulation model that can simulate the microvascular network structure is established.The fluid mechanics and particle tracking module of COMSOL are used to simulate the movement of red blood cells in the microvessel,and the different flow velocities are applied in the simulation.The corresponding relationship between the mean square displacement of red blood cells and the speed and time is obtained by processing the finite element simulation results.(3)A liquid phantom experimental device is designed and the measurement experiments are carried out.The optical data is collected using the DCS system platform.From the acquired data,the relationship between red blood cell displacement and speed and time are analyzed.In this paper,parameters such as mean square error(RMSE)and relative error(RE)are defined to quantitatively evaluate the results of computer simulation and phantom experiments.The results show that,whether it is computer simulation or liquid phantom experiment,the hybrid model has the best fit when fitting the data(specific performance: the highest accuracy(the minimum RMSE value in computer simulation and the minimum RE value in liquid simulation experiment))).The research results in this paper have greatly improved the traditional microvessel erythrocyte movement model,and have important clinical application value.