Fig. 8: Local blood flow velocity fluctuations measured using E-uPIV.

a Two regions of interest (ROIs) are selected. The color coding of flow direction is indicated with arrows. b Enlarged velocity maps and corresponding velocity profiles at selected cross sections within the ROIs. The sampled cross sections are marked as black lines. The light-shaded red region indicates the range of flow velocity fluctuations across the vessel’s cross-sectional area, while the solid line represents the mean velocity. c Speed measurements of a typical artery and vein at sampled cross sections (position indicated with white triangles) in ROI 2. The light-shaded red/blue region indicates the range of flow velocity fluctuations across the vessel’s cross-sectional area, while the solid line represents the mean velocity.