Quantitative imaging of red blood cell velocity invivo using optical coherence Doppler tomography

Abstract

We present particle counting ultrahigh-resolution optical Doppler tomography (pc-μODT) that enables accurate imaging of red blood cell velocities (ν RBC) of cerebrovascular networks by detecting the Doppler phase transients induced by the passage of a RBC through a capillary. We apply pc-μODT to image the response of capillary ν RBC to mild hypercapnia in mouse cortex. The results show that ν RBC in normocapnia (ν N 0.72 ± 0.15 mm/s) increased 36.1 ± 5.3 (ν H 0.98 ± 0.29 mm/s) in response to hypercapnia. Due to uncorrected angle effect and low hematocrit (e.g., ∼10), ν RBC directly measured by μODT were markedly underestimated (ν N ≈ 0.27 ± 0.03 mm/s, ν H ≈ 0.37± 0.05 mm/s). Nevertheless, the measured ν RBC increase (35.3) matched that (36.1 ± 5.3) by pc-μODT. © 2012 American Institute of Physics.