A theoretical framework for estimating cerebral oxygen metabolism changes using the calibrated-BOLD method: modeling the effects of blood volume distribution, hematocrit, oxygen extraction fraction, and tissue signal properties on the BOLD signal.
A theoretical framework for estimating cerebral oxygen metabolism changes using the calibrated-BOLD method: modeling the effects of blood volume distribution, hematocrit, oxygen extraction fraction, and tissue signal properties on the BOLD signal.
复制标题
DOI：
10.1016/j.neuroimage.2011.05.077
复制
发表时间：
2011-09-01
期刊：
影响因子：
5.7
通讯作者：
Buxton, Richard B.
中科院分区：
文献类型：
--
作者：
Griffeth, Valerie E. M.;Buxton, Richard B.
关键词：
校准血氧水平依赖（BOLD）成像是一种用于测量脑O2代谢变化的技术，它依赖于BOLD信号如何受脑血流量（CBF）和脑O2代谢率（CMRO 2）之间不匹配影响的准确模型。然而，其他因素，如休息时和激活时的脑血容量（CBV）分布也会影响BOLD信号。最初提出用于校准BOLD研究的Davis模型由于其简单性而被广泛使用，但它假设CBV变化均匀分布在血管腔室中，忽略血管内信号变化，并忽略血液-组织信号交换效应，因为CBV增加并取代组织体积。最近的研究表明，静脉CBV变化小于动脉变化，血管内信号变化和CBV交换效应可能会使估计的CMRO 2产生偏倚。在本文中，最近的实验结果之间的关系脱氧血红蛋白和BOLD信号的变化进行了整合，以模拟BOLD信号的详细扩展以前的模型，包括一个组织室和三个血液室，而不仅仅是静脉血室。然后使用模拟数据来测试校准BOLD的Davis模型的准确性，表明尽管模型原始推导的假设简单，但在典型CBF-CMRO 2耦合范围内估计的CMRO 2响应的误差是适度的。然而，可以通过放弃两个参数α和β的原始物理意义并将它们视为捕获几个物理效应的可调参数来提高模型的准确性。对于3特斯拉磁场和主动脉容积随激活而变化，Davis模型的准确性得到提高，新值为α=0.14和β=0.91。
Calibrated blood oxygenation level dependent (BOLD) imaging, a technique used to measure changes in cerebral O2 metabolism, depends on an accurate model of how the BOLD signal is affected by the mismatch between cerebral blood flow (CBF) and cerebral metabolic rate of O2 (CMRO2). However, other factors such as the cerebral blood volume (CBV) distribution at rest and with activation also affect the BOLD signal. The Davis model originally proposed for calibrated BOLD studies is widely used because of its simplicity, but it assumes CBV changes are uniformly distributed across vascular compartments, neglects intravascular signal changes, and ignores blood-tissue signal exchange effects as CBV increases and supplants tissue volume. More recent studies suggest that venous CBV changes are smaller than arterial changes, and that intravascular signal changes and CBV exchange effects can bias estimated CMRO2. In this paper, recent experimental results for the relationship between deoxyhemoglobin and BOLD signal changes are integrated in order to simulate the BOLD signal in detail by expanding a previous model to include a tissue compartment and three blood compartments rather than only the venous blood compartment. The simulated data were then used to test the accuracy of the Davis model of calibrated BOLD, demonstrating that the errors in estimated CMRO2 responses across the typical CBF-CMRO2 coupling range are modest despite the simplicity of the assumptions underlying the original derivation of the model. Nevertheless, the accuracy of the model can be improved by abandoning the original physical meaning of the two parameters α and β and treating them as adjustable parameters that capture several physical effects. For a 3 Tesla field and a dominant arterial volume change with activation, the accuracy of the Davis model is improved with new values of α=0.14 and β=0.91.
登录
查看更多内容
DOI：
10.3389/fnene.2010.00008
发表时间：
2010
期刊：
Frontiers in neuroenergetics
影响因子：
--
作者：
Buxton RB
通讯作者：
Buxton RB
影响因子：
5.7
作者：
Jones, M;Berwick, J;Mayhew, J
通讯作者：
Mayhew, J
DOI：
10.1073/pnas.83.4.1140
发表时间：
1986-02-01
影响因子：
11.1
作者：
FOX, PT;RAICHLE, ME
通讯作者：
RAICHLE, ME
影响因子：
5.7
作者：
Blockley, N. P.;Francis, S. T.;Gowland, P. A.
通讯作者：
Gowland, P. A.
影响因子：
8.3
作者：
GRUBB, RL;RAICHLE, ME;TERPOGOS.MM
通讯作者：
TERPOGOS.MM