Quantification of cell-free layer thickness and cell distribution of blood by optical coherence tomography

Abstract

Abstract. A high-speed optical coherence tomography (OCT) with 1-μm axial resolution was applied to assess the thickness of a cell-free layer (CFL) and a spatial distribution of red blood cells (RBC) next to the microchannel wall. The experiments were performed in vitro in a plain glass microchannel with a width of 2 mm and height of 0.2 mm. RBCs were suspended in phosphate buffered saline solution at the hematocrit level of 45%. Flow rates of 0.1 to 0.5 ml∕h were used to compensate gravity induced CFL. The results indicate that OCT can be efficiently used for the quantification of CFL thickness and spatial distribution of RBCs in microcirculatory blood flow.

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

“…As expected, the fluctuations are more pronounced in the vicinity of the walls, due to higher axial velocity gradients. The present results clearly show that the RMS value increases with the hematocrit, a fact that is in accordance with the findings of Lima et al [22] and Lauri et al [11]. The measurements reveal that that the quantity CFL/D, i.e., the CFL value normalized with respect to the hydraulic diameter, decreases with increasing Hct, which is in accordance with Namgung et al [6].…”

“…As expected, the fluctuations are more pronounced in the vicinity of the walls, due to higher axial velocity gradients. The present results clearly show that the RMS value increases with the hematocrit, a fact that is in accordance with the findings of Lima et al [22] and Lauri et al [11]. Figure 8 shows the RMS (root mean square) value of the instantaneous velocity measurement along the middle plane of the conduit reduced with respect to the mean velocity defined as U mean = Q/A.…”

“…This is clearly pronounced by relevant studies that attempt to estimate wall shear stress [8,9] or pressure drop [10] values in such vessels. Although this phenomenon is significant for diameters less than 300 µm, most of the published work is focused on vessel diameters between 20 and 100 µm, e.g., [6], or on fairly different geometries [11].…”

Yield and Electrical Functionality of the Glass-Laminated Conductive Wires and Connectors

“…Non-destructive structural characterization method, so called optical coherence tomography (OCT) was used in this study to evaluate structural changes caused by lamination and find reasons for the observed features of laminated electronics. OCT is widely used in (bio)medical measurements [18][19] but the same technology has been utilized also in industrial applications [17,[20][21][22][23][24][25][26][27] including the electronics quality inspection and reliability analysis [17,22]. Briefly described, OCT is a light-based imaging method in which backscattered intensity profiles are recorded and typically, by lateral scanning of a probing beam cross-sectional images are composed.…”

Quantitative depth‐resolved microcirculation imaging with optical coherence tomography angiography (Part ΙΙ): Microvascular network imaging

“…Simultaneous measurements of the thickness of cell‐free layer and spatial distribution of red blood cells can be achieved by averaging many A‐scans. The detection of individual cells may allow the study of the aggregation and deformability, and the estimation of hemoglobin content in red blood cells in the future …”