Cardiovascular Research Group, School of Human Sciences (Exercise and Sport Science), Faculty of Science, The University of Western Australia, Perth, AUSTRALIA.
School of Kinesiology, Faculty of Health and Behavioural Science, Lakehead University, Thunderbay, Ontario, CANADA.
Med Sci Sports Exerc. 2019 Jul;51(7):1558-1565. doi: 10.1249/MSS.0000000000001898.
Optical coherence tomography (OCT) is a novel high-resolution imaging technique capable of visualizing in vivo structures at a resolution of ~10 μm. We have developed specialized OCT-based approaches that quantify diameter, speed, and flow rate in human cutaneous microvessels. In this study, we hypothesized that OCT-based microvascular assessments would possess comparable levels of reliability when compared with those derived using conventional laser Doppler flowmetry (LDF).
Speckle decorrelation images (OCT) and red blood cell flux (LDF) measures were collected from adjacent forearm skin locations on 2 d (48 h apart), at baseline, and after a 30-min rapid local heating protocol (30°C-44°C) in eight healthy young individuals. OCT postprocessing quantified cutaneous microvascular diameter, speed, flow rate, and density (vessel recruitment) within a region of interest, and data were compared between days.
Forearm skin LDF (13 ± 4 to 182 ± 31 AU, P < 0.05) and OCT-derived diameter (41.8 ± 6.6 vs 64.5 ± 6.9 μm), speed (68.4 ± 9.5 vs 89.0 ± 7.3 μm·s), flow rate (145.0 ± 60.6 vs 485 ± 132 pL·s), and density (9.9% ± 4.9% vs 45.4% ± 5.9%) increased in response to local heating. The average OCT-derived microvascular flow response (pL·s) to heating (234% increase) was lower (P < 0.05) than the LDF-derived change (AU) (1360% increase). Pearson correlation was significant for between-day local heating responses in terms of OCT flow (r = 0.93, P < 0.01), but not LDF (P = 0.49). Bland-Altman analysis revealed that between-day baseline OCT-derived flow rates were less variable than LDF-derived flux.
Our findings indicate that OCT, which directly visualizes human microvessels, not only allows microvascular quantification of diameter, speed, flow rate, and vessel recruitment but also provides outputs that are highly reproducible. OCT is a promising novel approach that enables a comprehensive assessment of cutaneous microvascular structure and function in humans.
光学相干断层扫描（OCT）是一种新型的高分辨率成像技术，能够以约 10 μm 的分辨率可视化体内结构。我们已经开发了专门的基于 OCT 的方法，可定量测量人体皮肤微血管的直径、速度和血流率。在这项研究中，我们假设基于 OCT 的微血管评估与使用传统激光多普勒流量测定法（LDF）得出的评估具有相当的可靠性。
在 8 名健康年轻个体的前臂皮肤相邻位置上，分别在 2 天（相隔 48 小时）、基线和 30 分钟快速局部加热方案（30°C-44°C）后，采集散斑去相关图像（OCT）和红细胞通量（LDF）测量值。OCT 后处理定量了感兴趣区域内的皮肤微血管直径、速度、血流率和密度（血管募集），并对两天的数据进行了比较。
前臂皮肤 LDF（13±4 至 182±31 AU，P＜0.05）和 OCT 衍生的直径（41.8±6.6 至 64.5±6.9 μm）、速度（68.4±9.5 至 89.0±7.3 μm·s）、血流率（145.0±60.6 至 485±132 pL·s）和密度（9.9%±4.9%至 45.4%±5.9%）均随局部加热而增加。局部加热引起的 OCT 衍生微血管血流反应的平均值（pL·s）（234%增加）低于 LDF 衍生的变化（AU）（1360%增加）（P＜0.05）。Pearson 相关性分析显示，OCT 局部加热后的日间反应在流动方面具有显著相关性（r = 0.93，P＜0.01），但 LDF 无相关性（P = 0.49）。Bland-Altman 分析显示，日间基线 OCT 衍生的血流率的变异性小于 LDF 衍生的通量。
我们的研究结果表明，OCT 不仅可以直接可视化人体微血管，还可以对直径、速度、血流率和血管募集进行微血管定量，而且还提供了高度可重复的输出。OCT 是一种很有前途的新方法，可实现对人类皮肤微血管结构和功能的全面评估。
