Sudakou Aleh, Lange Frédéric, Isler Helene, Lanka Pranav, Wojtkiewicz Stanislaw, Sawosz Piotr, Ostojic Daniel, Wolf Martin, Pifferi Antonio, Tachtsidis Ilias, Liebert Adam, Gerega Anna
Nalecz Institute of Biocybernetics and Biomedical Engineering, Warsaw, Poland.
Department of Medical Physics and Biomedical Engineering, University College London, London, UK.
Biomed Opt Express. 2021 Sep 30;12(10):6629-6650. doi: 10.1364/BOE.431301. eCollection 2021 Oct 1.
We present and validate a multi-wavelength time-domain near-infrared spectroscopy (TD-NIRS) system that avoids switching wavelengths and instead exploits the full capability of a supercontinuum light source by emitting and acquiring signals for the whole chosen range of wavelengths. The system was designed for muscle and brain oxygenation monitoring in a clinical environment. A pulsed supercontinuum laser emits broadband light and each of two detection modules acquires the distributions of times of flight of photons (DTOFs) for 16 spectral channels (used width 12.5 nm / channel), providing a total of 32 DTOFs at up to 3 Hz. Two emitting fibers and two detection fiber bundles allow simultaneous measurements at two positions on the tissue or at two source-detector separations. Three established protocols (BIP, MEDPHOT, and nEUROPt) were used to quantitatively assess the system's performance, including linearity, coupling, accuracy, and depth sensitivity. Measurements were performed on 32 homogeneous phantoms and two inhomogeneous phantoms (solid and liquid). Furthermore, measurements on two blood-lipid phantoms with a varied amount of blood and Intralipid provide the strongest validation for accurate tissue oximetry. The retrieved hemoglobin concentrations and oxygen saturation match well with the reference values that were obtained using a commercially available NIRS system (OxiplexTS) and a blood gas analyzer (ABL90 FLEX), except a discrepancy occurs for the lowest amount of Intralipid. measurements on the forearm of three healthy volunteers during arterial (250 mmHg) and venous (60 mmHg) cuff occlusions provide an example of tissue monitoring during the expected hemodynamic changes that follow previously well-described physiologies. All results, including quantitative parameters, can be compared to other systems that report similar tests. Overall, the presented TD-NIRS system has an exemplary performance evaluated with state-of-the-art performance assessment methods.
我们展示并验证了一种多波长时域近红外光谱（TD-NIRS）系统，该系统无需切换波长，而是通过在整个选定波长范围内发射和采集信号来充分利用超连续光源的全部功能。该系统专为临床环境中的肌肉和大脑氧合监测而设计。脉冲超连续激光发射宽带光，两个检测模块中的每一个都采集16个光谱通道（每个通道使用宽度为12.5 nm）的光子飞行时间（DTOF）分布，每秒最多3次可提供总共32个DTOF。两根发射光纤和两个检测光纤束允许在组织上的两个位置或两个源 - 探测器间距处同时进行测量。使用三种既定协议（BIP、MEDPHOT和nEUROPt）对系统性能进行定量评估，包括线性、耦合、准确性和深度敏感性。在32个均匀体模和两个非均匀体模（固体和液体）上进行了测量。此外，在两个含有不同量血液和脂质乳剂的血脂体模上进行的测量为准确的组织血氧测定提供了最强有力的验证。除了脂质乳剂含量最低时出现差异外，所获取的血红蛋白浓度和氧饱和度与使用市售NIRS系统（OxiplexTS）和血气分析仪（ABL90 FLEX）获得的参考值匹配良好。对三名健康志愿者在前臂进行动脉（250 mmHg）和静脉（60 mmHg）袖带阻断期间的测量，提供了在遵循先前详细描述的生理过程的预期血流动力学变化期间进行组织监测的一个例子。所有结果，包括定量参数，都可以与报告类似测试的其他系统进行比较。总体而言，所展示的TD-NIRS系统通过最先进的性能评估方法评估具有 exemplary（此处可能有拼写错误，推测为“优异的”）性能。
