Ryerson University, Faculty of Science, Department of Physics, Toronto, Canada.
Institute for Biomedical Engineering, Science and Technology, Toronto, Canada.
J Biomed Opt. 2021 Mar;26(3). doi: 10.1117/1.JBO.26.3.036006.
We demonstrate the potential of probing the sO2 change under blood flow in vivo using photoacoustic (PA) imaging and sheds light on the complex relationship between RBC aggregation and oxygen delivery.
To conduct in vivo assessments of the sO2 in the radial artery of healthy volunteers and simultaneously probe the relation between the sO2 and hemodynamic behavior such as red blood cell (RBC) aggregation.
The effects of PA-based measurements of blood hemodynamics were studied as a function of the subjects' age (20s, 30s, and 40s). The pulsatile blood flow in the human radial artery of 12 healthy subjects was imaged in the 700 to 900 nm optical wavelength range using a linear array-based PA system.
The PA power when blood velocity is minimum (Pamax) was larger than the one attained at maximum blood velocity (Pamin), consistent with predictions based on the cyclical variation of RBC aggregation during pulsatile flow. The difference between Pamin and Pamax at 800 nm (ΔPa800) increased with age (1.7, 2.2, and 2.6 dB for age group of 20s, 30s, and 40s, respectively). The sO2 computed from Pamax was larger than the one from Pamin.
The ΔPa800 increased with participant age. The ΔPa800 metric could be a surrogate of noninvasively monitoring the age-induced changes in RBC aggregation. The sO2 change during a cycle of pulsatile blood flow also increased with age, demonstrating that RBC aggregation can affect the sO2 change.
我们通过光声（PA）成像证明了在体内探测血流下 sO2 变化的潜力，并揭示了 RBC 聚集与氧输送之间复杂的关系。
对健康志愿者桡动脉中的 sO2 进行体内评估，并同时探测 sO2 与血流动力学行为（如 RBC 聚集）之间的关系。
研究了基于 PA 的血液动力学测量的影响，作为受试者年龄（20 多岁、30 多岁和 40 多岁）的函数。使用基于线性阵列的 PA 系统，在 700 到 900nm 的光学波长范围内对 12 名健康受试者的人类桡动脉中的脉动血流进行成像。
当血流速度最小时（Pamax）的 PA 功率大于最大血流速度时的功率（Pamin），这与基于脉动流期间 RBC 聚集的周期性变化的预测一致。在 800nm 处 Pamin 和 Pamax 之间的差异（ΔPa800）随年龄增加而增加（20 多岁、30 多岁和 40 多岁的年龄组分别为 1.7、2.2 和 2.6dB）。从 Pamax 计算出的 sO2 大于从 Pamin 计算出的 sO2。
ΔPa800 随参与者年龄增加而增加。ΔPa800 指标可以作为非侵入性监测 RBC 聚集随年龄变化的替代指标。在脉动血流的一个循环期间，sO2 的变化也随年龄增加而增加，这表明 RBC 聚集会影响 sO2 的变化。
