Noninvasive determination of the optical properties of adult brain: near-infrared spectroscopy approach
Noninvasive determination of the optical properties of adult brain: near-infrared spectroscopy approach
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DOI：
10.1117/1.1628242
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发表时间：
2004-01-01
影响因子：
3.5
通讯作者：
Gratton, E
中科院分区：
文献类型：
--
作者：
Choi, J;Wolf, M;Gratton, E
近红外光谱提供的生理测量的基本参数是局部吸收和散射系数。对于成年人的头部，由于头部的分层结构，它们很难进行无创测量。本文报道了用多距离频域法测量30名成年志愿者额头吸收系数和减少散射系数的结果。光电二极管的分离距离为10 ~ 80 mm，测量值分别为758和830 nm。测量的前额吸收和减少散射系数用于评估头皮和大脑中的血红蛋白含量以及脑氧饱和度。我们发现脑氧合在受试者组内分布相对狭窄（头皮和脑的标准差分别约为3%和6%），而血红蛋白浓度分布相对较广。我们发现，随着光电器件距离的增加，吸收系数增大，散射系数减小，分别反演出较短和较长的光电器件距离下头皮和大脑的光学值。我们给出了吸收和散射系数随光电二极管距离的变化曲线。为了验证每一层的数值，将实验数据与基于成人头部两层模型的预测结果进行了比较。两层模型的头皮和颅骨厚度是通过对受试者头部进行磁共振成像得到的。由两层模型得到的光学参数与用多距离法测得的光学参数吻合良好。(C) 2004光学仪器工程师学会。
The basic parameters for physiological measurements provided by near-infrared spectroscopy are the local absorption and scattering coefficients. For the adult human head, they have been difficult to measure noninvasively because of the layered structure of the head. The results of measurements of absorption and reduced scattering coefficients through the forehead on 30 adult volunteers using a multi-distance frequency domain method are reported. The optode separation distance ranged from 10 to 80 mm and measurements were recorded at 758 and 830 nm. The measured absorption and reduced scattering coefficients of the forehead were used to evaluate the hemoglobin content in the scalp and brain as well as cerebral oxygen saturation. We found that cerebral oxygenation was relatively narrowly distributed within the subject group (the standard deviation was about 3% for scalp and 6% for brain, respectively), whereas hemoglobin concentrations had a relatively broader distribution. We found that as the optode distance increased, the absorption coefficients increased and the scattering coefficients decreased, retrieving the optical values of scalp and brain for shorter and longer optode distances, respectively. We present the transition curves of the absorption and reduced scattering coefficients as functions of the optode distance. In order to verify the values for each layer, a comparison between the experimental data and a prediction based on the two-layer model of the adult head was carried out. The thicknesses of scalp and skull for the two-layer model were obtained by magnetic resonance imaging of a subject's head. The optical parameters obtained from the two-layer model agreed very well with those measured by the multidistance method. (C) 2004 Society of Photo-Optical Instrumentation Engineers.