High speed versus pulsed images for micro-particle image velocimetry: a direct comparison of red blood cells versus fluorescing tracers as tracking particles

Abstract

High speed photography in micro-particle image velocimetry (μPIV) using red blood cells as tracer particles and the use of fluorescing tracer particles (in conjunction with pulsed images) are directly compared by using both methods simultaneously. Measurements are taken on the same blood sample in the same microchip using both methods. This work directly and statistically compares the two methods of μPIV measurement in a controlled in vitro environment for the first time in literature. The pulsed method using fluorescing tracer particles is found to decrease the depth of correlation as expected, and to better represent the shape of the velocity profile. Two methods of velocity characterization are used (single and double parameter) and the pulsed images provide better shape representation in both cases.

Experimental and Numerical Study of Blood Flow in μ-vessels: Influence of the Fahraeus–Lindqvist Effect

“…More precisely, for low volumetric flowrates, the settling velocity of the RBCs is of the same order of magnitude as the axial velocity of the main flow. To confirm this belief, we performed experiments with similar flow rates as those reported [14]; that is, 0.01 mL/h, and we recorded the motion of the RBCs at three planes of the micro-channel, i.e., bottom, middle, and top ( Figure 6). As the fluid velocity decreases, the settling velocity of the RBCs (vertical velocity component U t = 6.2 × 10 −4 m/s) is comparable to their horizontal velocity, resulting in the settling of the RBCs before exiting the test section.…”

“…Blood velocity measurements for flow rates ranging from 5 to 10 mL/h, presented in Figure 5, reveal that the axial velocity distribution, i.e., blunted parabolic velocity profiles, is practically the same regardless of the tracing method employed. However, Pitts and Fenech [14],who used the same tracing methods, found a significant difference between the velocities obtained by the two methods. We believe that this discrepancy may be attributed to the low volumetric flow rates they had in their experiments (two orders of magnitude lower than our flow rates).…”

“…We employed two different tracing methods, i.e., coloured RBCs or standard PIV tracers. Previous studies suggested that the two tracing methods give significant different results [14]. This issue is clarified in this study.…”

Microfluidics Approach to the Mechanical Properties of Red Blood Cell Membrane and Their Effect on Blood Rheology

“…Eventually, high-speed and high-resolution cameras, with an enhanced sensitivity and mounted to an optical microscope, enabled velocity measurements of such small-scale flows. In this aspect, several techniques have been developed to measure the velocity fields of blood and RBCs at the microscale, such as µPIV (microparticles image velocimetry) or PTV (particle tracking velocimetry) and wavelet-based optical flow velocimetry (wOFV) [95][96][97][98][99]. 5), is averaged for different initial conditions of the RBC.…”

Cell-free layer measurements ofin vitroblood flow in a microfluidic network: an automatic and manual approach

“…For low concentration of blood cells, the micro-PIV methodology is a suitable approach to study blood flow phenomena in microcirculation (Popel & Johnson 2005;Lima et al 2006Lima et al , 2008Garcia & Lima 2012;Pitts & Fenech 2013;Mehri et al 2014). However, for high concentration of blood cells the light absorbed by the cells contributes to decrease the concentration of tracer particles in the acquired images which promotes errors in the micro-PIV measurements (Lima et al 2007).…”