Study On The Relation Between Hemorhological Properties And Dielectric Properties Of Blood

Blood disease has become one of the most common diseases affecting human health. C urrently, most of blood detecting methods are invasive or implemented in vitro, which might only hurt the human body, but also difficult to detect properties of blood accurately. In general, Blood diseases occur accompanied by changes in hemorheology, affecting the overall dielectric properties of blood thereby. As a result, studying on the relationship between hemorheological and dielectric properties of blood can facilitate the non- invasive detection of blood properties, which adopt the electromagnetic methods. Moreover, it plays a significant role in diagnosing of certain blood disorders.This paper focuses on the research of relationships between dielectric properties, namely permittivity and conductivity, a nd rheological properties of blood. First, relevant theories of dielectric properties of blood are introduced, which are based on the classical three-element model of blood. According to the contrast among several dielectric properties measurement methods, such as impedance method and the electrical bridge method, a combination of second-electrode method and four-electrode method is selected as the ultimate measuring method. In addition, this thesis introduces the related theory of blood rheology, exploring the hematocrit, red blood cell deformability, aggregation and other factors that affect blood viscosity as a focal point, and summing up the measuring indexes and methods of hemorrheology characteristics.Secondly, a theoretical model of the relationship between the conductivity of flowing blood and hemorheological properties is derived in detail, which is based on the Maxwell-Frick equation of dynamic blood. Furthermore, the relation of blood dielectric constant and rheology characteristics is explored, as a result of which an elementary relationship between the dielectric constant and flow velocity, blood apparent viscosity, hematocrit and other parameters is established. The simultaneous measuring system of dynamic dielectric properties of blood and rheology characteristics are also introduced in this paper, laying the foundation for the real- time study of the relationship between the two properties.Finally, the dielectric properties of blood were measured e xperimentally in the frequency range between 10 k Hz-100 MHz based on a hyperlipidemia rabbit model. The dielectric constant and conductivity of different concentrations of sodium chloride solution are measured in the experiment firstly. Then, by comparing the measured data with the theoretical data of sodium chloride solution, the accuracy of the measurement system is verified. O n this basis of the verification, dielectric properties of blood flow under different hemorheological conditions are measured. Further, regression analysis show a strong correlation between the rheological and dielectric properties of blood.