Quantitative investigation of the effect of the extra-cerebral vasculature in diffuse optical imaging: a simulation study.
Quantitative investigation of the effect of the extra-cerebral vasculature in diffuse optical imaging: a simulation study.
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DOI：
10.1364/boe.2.000680
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发表时间：
2011-02-23
影响因子：
3.4
通讯作者：
Benali H
中科院分区：
文献类型：
--
作者：
Dehaes M;Gagnon L;Lesage F;Pélégrini-Issac M;Vignaud A;Valabrègue R;Grebe R;Wallois F;Benali H
弥散光学成像（DOI）是一种非侵入性的技术，可以恢复大脑中的血流动力学变化。由于混浊介质中光子传播的扩散性质以及大脑组织位于成人头皮下约1.5 cm的事实，DOI测量受到部分体积误差的影响。DOI测量也对大软脑膜血管敏感，因为氧合和脱氧血红蛋白是近红外窗口中的主要发色团。在这项研究中，研究了矢状窦附近的脑外血管系统对在人类成人视觉皮质上模拟的DOI测量的影响。数值Monte Carlo模拟进行了两个特定的模型，来自磁共振成像（MRI）扫描的人的头部。第一个模型包括脑外血管系统，其中假设血红蛋白浓度恒定，而第二个模型则没有。通过比较来自不同光学阵列和激活区域的每个模型的恢复的血红蛋白变化来量化脉管系统的筛选效应。在每种情况下，计算校正因子，说明恢复和模拟血红蛋白变化之间的差异。结果表明，当对脑外血管系统进行建模时，血红蛋白浓度的变化可以更好地估计，并且在这种情况下获得的校正因子至少低1.4倍。还在高密度漫射光学断层扫描配置中检查了血管系统的影响。在这种情况下，每种模型回收的血红蛋白浓度变化之间的差异降至10%。
Diffuse optical imaging (DOI) is a non invasive technique allowing the recovery of hemodynamic changes in the brain. Due to the diffusive nature of photon propagation in turbid media and the fact that cerebral tissues are located around 1.5 cm under the adult human scalp, DOI measurements are subject to partial volume errors. DOI measurements are also sensitive to large pial vessels because oxygenated and deoxygenated hemoglobin are the dominant chromophores in the near infrared window. In this study, the effect of the extra-cerebral vasculature in proximity of the sagittal sinus was investigated for its impact on DOI measurements simulated over the human adult visual cortex. Numerical Monte Carlo simulations were performed on two specific models of the human head derived from magnetic resonance imaging (MRI) scans. The first model included the extra-cerebral vasculature in which constant hemoglobin concentrations were assumed while the second did not. The screening effect of the vasculature was quantified by comparing recovered hemoglobin changes from each model for different optical arrays and regions of activation. A correction factor accounting for the difference between the recovered and the simulated hemoglobin changes was computed in each case. The results show that changes in hemoglobin concentration are better estimated when the extra-cerebral vasculature is modeled and the correction factors obtained in this case were at least 1.4-fold lower. The effect of the vasculature was also examined in a high-density diffuse optical tomography configuration. In this case, the difference between changes in hemoglobin concentration recovered with each model was reduced down to 10%.