Basic study on measurement of quantitative cerebral hemoglobin concentration using the full spectrum near infrared spectroscopy

脑血流动力学和脑氧合的实时测量对新生儿脑损伤的预防和治疗非常重要。我们利用全光谱近红外光谱（fsNIRS），利用指数修正方程将平坦化的非线性扩散光谱转换为非平坦化的线性透射光谱，并进行多分量最小二乘曲线拟合，然后对各个光谱之间的不同光程长度进行归一化处理。在这项研究中，我们开发了一种新的分析系统，它允许光学光谱测量半定量脑血红蛋白浓度和脑血管饱和度。在体外实验中，我们发现新方法得到的总血红蛋白浓度与时间分辨光谱测定的总血红蛋白浓度（1%脂内溶液中0 ~ 81.4 μM的血红蛋白浓度）具有显著的相关性（r = 0.895, p < 0.0001）。在新生仔猪体内换血实验中，两种方法测定的脑总血红蛋白浓度和脑总血红蛋白饱和度与体外实验结果均存在显著相关性（r = 0.944, p < 0.0001; r = 0.858, p < 0.0001）。我们所称的碱基与时间分辨光谱测定的光程长度有很好的关系。因此，我们认为可以比较从不同受试者获得的值。

Real-time measurement of cerebral hemodynamics and oxygenation are very important for the prevention and management of brain damage in neonates. We have previously reported, using the full spectrum near infrared spectroscopy (fsNIRS), conversion of the flattened and nonlinear diffusion spectra to the non flattened and linear transmission spectra by exponential correction equation, and multi-component least square curve fitting and then normalization of different light path-lengths among individual spectra.In this study, we have developed a new analytical system, which allows optical spectroscopic measurements of semiquantitative cerebral hemoglobin concentration and cerebrovasucular saturation.In vitro experiment, we found a significant correlation (r = 0.895, p < 0.0001) between total hemoglobin concentration obtained by our new methods and this measured by time resolved spectroscopy (0 〜 81.4 μM of hemoglobin concentration in 1% intralipid solution). In vivo experiments of blood exchange transfusion in newborn piglets, significant correlations (r = 0.944, p < 0.0001 ; r = 0.858, p < 0.0001 respectively) among the respect cerebral total hemoglobin concentration and the respect hemoglobin saturation determined by the two methods were also observed as well as the result in vitro. The base which we call had a good relationship with optical path length determined by time resolved spectroscopy. Therefore, we consider that it is possible to compare the values obtained from different subjects.