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Advisor(s)
Abstract(s)
Developments in optical experimental techniques have helped in elucidating how blood flows through
microvessels. Although initial developments were encouraging, studies on the flow properties of blood in
microcirculation have been limited by several technical factors, such as poor spatial resolution and difficulty
obtaining quantitative detailed measurements at such small scales. Recent advances in computing, microscopy,
and digital image processing techniques have made it possible to combine a particle tracking velocimetry (PTV)
system with a confocal microscope. We document the development of a confocal micro-PTV measurement
system for capturing the dynamic flow behavior of red blood cells (RBCs) in concentrated suspensions.
Measurements were performed at several depths through 100-mm glass capillaries. The confocal micro-PTV
system was able to detect both translational and rotational motions of individual RBCs flowing in concentrated
suspensions. Our results provide evidence that RBCs in dilute suspensions (3% hematocrit) tended to follow
approximately linear trajectories, whereas RBCs in concentrated suspensions (20% hematocrit) exhibited
transversal displacements of about 2% from the original path. Direct and quantitative measurements indicated
that the plasma layer appeared to enhance the fluctuations in RBC trajectories owing to decreased obstruction in
transversal movements caused by other RBCs. Using optical sectioning and subsequent image contrast and
resolution enhancement, the system provides previously unobtainable information on the motion of RBCs,
including the trajectories of two or more RBCs interacting in the same focal plane and RBC dispersion
coefficients in different focal planes.
Description
Keywords
Red blood cells Microcirculation Microchannel Blood flow Confocal micro-PTV RBC dispersion
Pedagogical Context
Citation
Lima, R.; Ishikawa, T.; Imai, Y.; Takeda, M.; Wada, S.; Yamaguchi, T. (2009). Measurement of individual red blood cell motions under high hematocrit conditions using a confocal micro-PTV system. Annals of Biomedical Engineering. ISSN 1573-9686. 37:8, p.1546-1559