Can the cerebral metabolic rate of oxygen be estimated with near-infrared spectroscopy?
Can the cerebral metabolic rate of oxygen be estimated with near-infrared spectroscopy?
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DOI：
10.1088/0031-9155/48/15/311
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发表时间：
2003-08-07
影响因子：
3.5
通讯作者：
Mandeville, JB
中科院分区：
文献类型：
--
作者：
Boas, DA;Strangman, G;Mandeville, JB
我们使用近红外光谱 (NIRS) 测量了在短暂的手指敲击练习中成人大脑中氧合血红蛋白和脱氧血红蛋白的变化。可以根据提供某些模型假设的这些 NIRS 数据来估计脑氧代谢率 (CMRO2)。 CMRO2的变化与总血红蛋白浓度、脱氧血红蛋白浓度和血流量的变化有关。由于 NIRS 无法测量大脑激活期间血流的动态变化，因此我们依赖于将动态血量和血流变化联系起来的 Windkessel 模型，该模型之前已用于根据功能磁共振成像 (fMRI) 数据估计 CMRO2。由于部分体积效应，我们无法用 NIRS 量化局部脑血红蛋白浓度的绝对变化，因此无法获得 CMRO2 绝对变化的估计。流量-体积关系的不确定性也会使绝对估计变得混乱。然而，流量变化与 CMRO2 变化之比对这些不确定性相对不敏感。对于手指敲击任务，我们估计最可能的流量消耗比为 1.5 到 3，与文献中先前的发现一致，尽管我们不能排除 CMRO2 没有变化的可能性。该比率的大范围源于必须根据数据估计的大量模型参数。对流量消耗比的更精确估计将需要对模型参数或流量信息进行更好的估计，这可以通过将 NIRS 与 fMRI 相结合来提供。
We have measured the changes in oxy-haemoglobin and deoxy-haemoglobin in the adult human brain during a brief finger tapping exercise using near-infrared spectroscopy (NIRS). The cerebral metabolic rate of oxygen (CMRO2) can be estimated from these NIRS data provided certain model assumptions. The change in CMRO2 is related to changes in the total haemoglobin concentration, deoxy-haemoglobin concentration and blood flow. As NIRS does not provide a measure of dynamic changes in blood flow during brain activation, we relied on a Windkessel model that relates dynamic blood volume and flow changes, which has been used previously for estimating CMRO2 from functional magnetic resonance imaging (fMRI) data. Because of the partial volume effect we are unable to quantify the absolute changes in the local brain haemoglobin concentrations with NIRS and thus are unable to obtain an estimate of the absolute CMRO2 change. An absolute estimate is also confounded by uncertainty in the flow-volume relationship. However, the ratio of the flow change to the CMRO2 change is relatively insensitive to these uncertainties. For the finger tapping task, we estimate a most probable flow-consumption ratio ranging from 1.5 to 3 in agreement with previous findings presented in the literature, although we cannot exclude the possibility that there is no CMRO2 change. The large range in the ratio arises from the large number of model parameters that must be estimated from the data. A more precise estimate of the flow-consumption ratio will require better estimates of the model parameters or flow information, as call be provided by combining NIRS with fMRI.