Velocity Profiles of Pulsatile Blood Flow in Arterioles with Bifurcation and Confluence in Rat Mesnetery Measured by Particle Image Velocimetry

Abstract

Blood flow velocity profile in microvessels is essential for in vivo studies of substance exchange between blood and tissue. This paper was aimed to investigate the temporal and spatial variations in the velocity profile of red blood cell (RBC) flow in arterioles with both bifurcation and confluence in the rat mesentery, using a particle image velocimetry (PIV). The microcirculation in rat mesentery was observed under a microscopic system with a high-speed digital camera. The images of RBCs flow in microvessels were recorded simultaneously with the arterial blood pressure. Based on the high-speed video images, instantaneous velocity vectors of RBCs in arterioles with bifurcation and confluence were evaluated using a high spatial-resolution PIV algorithm. Then, the time-averaged and ensemble-averaged velocity profiles over the cross-section were calculated from the proximal through the bifurcation to the distal to the confluence. The velocity profile of RBCs showed two peaks at bifurcation and confluence, respectively. The double peaks were most marked at the apex of bifurcation, but not so much marked at the confluence. The variation of centerline velocity showed that the length of vessel under the influence of bifurcation or confluence, was approximately 1.5 times the diameter at the proximal to the apex of bifurcation, but its length was reduced significantly at the distal of confluence.

Asymmetry of red blood cell motions in a microchannel with a diverging and converging bifurcation

“…[17][18][19][20] However, the majority of these studies relied predominantly on the data collected in simple geometries. Few hemodynamic studies, such as the work of Nakano et al, 21 Barber et al, 22 Yang et al, 23 and Doyeux et al, 24 were performed in bifurcations composed of capillary-sized vessels. Far less work has been published on the blood flow through bifurcations with dimensions comparable to arteriole-sized vessels.…”

“…The complexity of controlling and obtaining detailed measurements of the blood flow behavior through in vivo microvascular systems 21 has led to in vitro studies being performed by using polydimethylsiloxane (PDMS) microchannels obtained by means of a soft-lithography technique. [30][31][32][33] Very recently, we have studied the asymmetry of blood flow in a microchannel with a symmetric bifurcation and confluence.…”

In vitro confocal micro-PIV measurements of blood flow in a square microchannel: The effect of the haematocrit on instantaneous velocity profiles

“…The velocity profiles of blood flow in vivo and in vitro have been measured using several techniques, including double-slit photometry (Gaehtgens et al, 1970;Baker and Wayland, 1974), video microscopy and image analysis (Bugliarello et al, 1963;Tangelder et al, 1986;Parthasarathi et al,1999), laser-Doppler anemometry (Einav et al, 1975;Born et al, 1978;Cochrane et al, 1981;Uijttewaal et al, 1994, Golster et al, 1999, and particle-measuring methods (Sugii et al, 2002Nakano et al, 2003Nakano et al, , 2005Jeong et al, 2006). Nevertheless, no general consensus yet exists concerning the actual velocity profile in microvessels.…”

A multi‐component lattice Boltzmann model with non‐uniform interfacial tension module for the study of blood flow in the microvasculature

“…Assuming that blood density at normal temperature is = 1.05 g/cm 3 as was stated by Nakano and Sugii [19] and that the velocity of the RBCs is representative of the average blood velocity in the capillary, then the estimated blood viscosity is = 2.35 cP and the average Reynolds number is Re ≈ 0.0055 for a random capillary size. A domain of 19×450 lattice sites was selected for the simulation of four droplets where all variables were measured in lattice units.…”