Blood Flow Velocity Measurement in the Microcirculation Using Highly Accurate Iterative PIV (2nd Report, Analysis of Ensemble Averaged Velocity in Rat Mesenteric Arterioles)

Blood flow in microvessels, such as arterioles, capillaries and venules, whose diameter ranges from 5 to 50 μm, is responsible for the maintenance of tissue and organ functions. The measurement of microvascular blood flow velocity with high measurement accuracy is essential for basic and clinical studies in the assessment of flow shear stress at the vascular wall in relation to substance exchange between blood and tissue. This paper aimed to evaluate the velocity field of blood flow in microvessels with high spatial and temporal resolution. By using micro PIV system, the velocity distributions of red blood cells flowing in rat mesenteric arterioles, including near the wall in the axisymmetric plane, were obtained. Ensemble averaged time-series of velocity profiles in the cross-sections were calculated for comparison. It was shown that the arteriole velocity profile was blunt in the center region of the vessel cross-section while it was steep in the near wall region.