A quantitative comparison of simultaneous BOLD fMRI and NIRS recordings during functional brain activation
A quantitative comparison of simultaneous BOLD fMRI and NIRS recordings during functional brain activation
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DOI：
10.1006/nimg.2002.1227
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发表时间：
2002-10-01
期刊：
影响因子：
5.7
通讯作者：
Boas, DA
中科院分区：
文献类型：
--
作者：
Strangman, G;Culver, JP;Boas, DA
近红外光谱（NIRS）已被用于无创监测成人的大脑功能在各种各样的任务。虽然在这些实验中发现了与功能性磁共振成像（fMRI）生成的地图的粗略空间对应关系，但两种记录方式之间的幅度对应关系尚未得到充分表征。为此，我们同时获得了lirs和血氧水平依赖（BOLD）的fMRI数据，并将Delta(1BOLD)（近似toR(2)*）与执行简单运动任务的受试者的lirs数据得出的氧合血红蛋白、脱氧血红蛋白和总血红蛋白浓度的变化进行了比较。我们预计与脱氧血红蛋白的相关性最强，因为脱氧血红蛋白浓度的变化与BOLD信号之间存在因果关系。相反，我们发现了高度可变的相关性，这表明需要在我们的NIBS计算中考虑个体受试者的差异。我们认为，变异是由与每个信号相关的系统误差造成的，包括：(1)由焦浓度变化引起的部分体积误差，(2)部分体积效应的波长依赖性，(3)组织模型误差，以及(4)氧血红蛋白和脱氧血红蛋白浓度变化之间可能的空间不一致。在考虑了这些影响后，发现功能磁共振成像变化与所有光学测量之间存在很强的相关性，其中氧合血红蛋白提供了最强的相关性。重要的是，即使在平均BOLD信号中包括头皮、头骨和非活动脑组织时，这一发现也成立。这至少在一定程度上反映了氧血红蛋白相对于脱氧血红蛋白的优越的噪比（来自光学测量），而不是与BOLD信号解释相关的生理学。(C) 2002 Elsevier Science （USA）。
Near-infrared spectroscopy (NIRS) has been used to noninvasively monitor adult human brain function in a wide variety of tasks. While rough spatial correspondences with maps generated from functional magnetic resonance imaging (fMRI) have been found in such experiments, the amplitude correspondences between the two recording modalities have not been fully characterized. To do so, we simultaneously acquired LAIRS and blood-oxygenation level-dependent (BOLD) fMRI data and compared Delta(1BOLD) (approximate toR(2)*) to changes in oxyhemoglobin, deoxyhemoglobin, and total hemoglobin concentrations derived from the LAIRS data from subjects performing a simple motor task. We expected the correlation with deoxyhemoglobin to be strongest, due to the causal relation between changes in deoxyhemoglobin concentrations and BOLD signal. Instead we found highly variable correlations, suggesting the need to account for individual subject differences in our NIBS calculations. We argue that the variability resulted from systematic errors associated with each of the signals, including: (1) partial volume errors due to focal concentration changes, (2) wavelength dependence of this partial volume effect, (3) tissue model errors, and (4) possible spatial incongruence between oxy- and deoxyhemoglobin concentration changes. After such effects were accounted for, strong correlations were found between fMRI changes and all optical measures, with oxyhemoglobin providing the strongest correlation. Importantly, this finding held even when including scalp, skull, and inactive brain tissue in the average BOLD signal. This may reflect, at least in part, the superior contrast-to-noise ratio for oxyhemoglobin relative to deoxyhemoglobin (from optical measurements), rather than physiology related to BOLD signal interpretation. (C) 2002 Elsevier Science (USA).