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

摘要

We present particle counting ultrahigh-resolution optical Doppler tomography (pc-μODT) that enables accurate imaging of red blood cell velocities (v_(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 v_(RBC) to mild hypercapnia in mouse cortex. The results show that v_(RBC) in normocapnia (v_n = 0.72 ±0.15 mm/s) increased 36.1% ±5.3% v_H = 0.98 ± 0.29 mm/s) in response to hypercapnia. Due to uncorrected angle effect and low hematocrit (e.g., ~10%), i^rbc directly measured by μODT were markedly underestimated (v_N ≈ 0.27 ± 0.03 mm/s, u_H ≈ 0.37 ±0.05 mm/s). Nevertheless, the measured v_(RBC) increase (35.3%) matched that (36.1% ±5.3%) by pc-μODT.