NON-INVASIVE METHOD OF BLOOD RHEOLOGICAL PROPERTIES COMPLEX ANALYSIS IN VIVO Russian patent published in 2017 - IPC A61B5/26 A61B8/06 G01N11/02 

FIELD: medicine.

SUBSTANCE: in the zone of interest, the flow of blood through the vessel is probed with pulses of ultrasonic oscillations in the energy colour Doppler coding mode. The diameter d of the vessel, the thickness of the blood flow boundary layer, the area of the blood flow boundary layer, the area of axial blood flow, the cardiac contractions frequency are determined and parameters characterizing the blood rheological properties are calculated based on the obtained data: blood kinematic viscosityν, the Womersley number α, parameter α², ε flow structure coefficient. The peak systolic velocity Vps of axial blood flow and the mean maximum velocity Vm of axial flow of blood are determined, the inter-intimal diameter of the vessel and the Reynolds number Re, shear rate V, and shear voltage τ are calculated based on these parameters. Intubation is carried out with a traffic intensity distribution map over the flow section and the following is further determined using the measurements: area Sos of the axial flow into the systole, area Sns of the flow into the systole, area Sod of the axial flow into the diastole, area Snd of the flow into the diastole, area Sδs into the systole, area Sδd into the diastole, systole time ts, diastole time td, heart cycle time t; and the following is calculated from the obtained data: averaged thickness δxs of the boundary layer into the systole (cm) according to the formula: δxs=Sδs/[√π*(√Sns+√Sos)], where Sδs is the area of the boundary layer into the systole, Sns is the flow area into the systole, Sos is the axial flow area into the systole; averaged thickness δxd of the boundary layer into the diastole (cm) according to the formula: δxd=Sδd/[√π*(√Snd+√Sod)], where Sδd is the boundary layer area into the diastole, Snd is the flow area into the diastole, Sod-ω is angular velocity (c^-1); νs - blood kinematic viscosity into the systole (cSt) according to the formula: νs=ωδxs²; d - blood kinematic viscosity into the diastole (cSt) according to the formula: νd=ωδxd²; νh - blood hemodynamic viscosity (cSt) according to the formula: νh=[(νs x ts)+(νd x td)]/t; Σhs - coefficient of rheological effectiveness of blood flow into the systole according to the formula: Σhs=Sos/Sns, where Sos is the area of the axial flow into the systole; Sns is the area of the flow into the systole; Σhd - coefficient of rheological efficiency of blood flow into the diastole according to the formula: Σhd=Sod/Snd, where Sod is the area of the axial flow into the diastole; Snd is the flow area into the diastole; Σh - coefficient of rheological efficiency of blood flow per cardiac cycle according to the formula: Σh=[(Σhs x ts)+(Σhd x td)]/t. Erythrocytes movement characteristics are determined in the axial flow, such as motion intensity, evaluating it according to the level of colour intensity of colouring of the axial flow colour map, comparing it to the intensity level of the colour scale on the monitor screen; degree of flow disorganization according to the structure and degree of heterochromicity of the axial flow colour map, for which the axial flow structural coefficient AFSC is determined as the ratio of the area of axial flow sections with the maximum colouring intensity Sm and the axial flow area So, and at AFSC=1 flow structure is considered normally organized, and at AFSC<1 - disorganized; the erythrocyte movement intensity gradient in the direction from the vessel wall to the axial flow, estimating the degree of flow local stability by the nature of axial flow contours and boundary layer strips, the degree of axial flow cantering and the uniformity of the boundary layer thickness over the vessel section.

EFFECT: improved efficiency of the analysis of blood rheological properties due to calculation of a large number of quantitative rheological characteristics of the blood flow and visual detection, which allows to localize the vessel sections with violated hemorheological parameters.

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