BOLD-specific cerebral blood volume and blood flow changes during neuronal activation in humans
BOLD-specific cerebral blood volume and blood flow changes during neuronal activation in humans
复制标题
DOI：
10.1002/nbm.1411
复制
发表时间：
2009-12-01
影响因子：
2.9
通讯作者：
Pike, G. Bruce
中科院分区：
文献类型：
--
作者：
Chen, J. Jean;Pike, G. Bruce
为了理解和预测血氧水平依赖（BOLD）功能性磁共振成像（fMRI）信号，准确了解脑血流量（ΔCBF）和脑血容量（ΔCBV）变化之间的关系至关重要。目前，这种关系被广泛假定为具有由灵长类动物数据得出的格鲁布幂律特征，其中幂系数（α）被发现为0.38。这种通用公式的有效性此前已被检验过，并且在使用校准的BOLD计算脑氧代谢变化（ΔCMRo₂）时，0.38的α值经常被引用。然而，这种关系的直接应用一直是一些争论的主题，因为众所周知，BOLD信号主要受“静脉”CBV（ΔCBVv，包括毛细血管、小静脉以及在较小程度上小动脉隔室中的脱氧血液）的变化调节，而非总CBV，然而人类的ΔCBVv测量却极其稀少。在这项工作中，我们利用用于体积估计的静脉重聚焦（VERVE）技术展示了在3T下可重复的ΔCBVv测量，并报告了在接受分级视觉和感觉运动刺激的人类受试者中稳态的ΔCBVv和ΔCBF测量结果。我们发现：（1）一种特定于BOLD的流量 - 体积幂律关系由α = 0.23 ± 0.05描述，明显低于总CBV的格鲁布常数0.38；（2）在视觉和感觉运动区域之间未发现该幂律常数有显著差异；（3）在梯度回波BOLD建模中使用格鲁布值0.38会导致对ΔCMRo₂的低估。版权所有（C）2009约翰威立父子有限公司
To understand and predict the blood-oxygenation level-dependent (BOLD) fMRI signal, an accurate knowledge of the relationship between cerebral blood flow (Delta CBF) and volume (Delta CBV) changes is critical. Currently, this relationship is widely assumed to be characterized by Grubb's power-law, derived from primate data, where the power coefficient (alpha) was found to be 0.38. The validity of this general formulation has been examined previously, and an alpha of 0.38 has been frequently cited when calculating the cerebral oxygen metabolism change (Delta CMRo(2)) using calibrated BOLD. However, the direct use of this relationship has been the subject of some debate, since it is well established that the BOLD signal is primarily modulated by changes in 'venous' CBV (Delta CBVv, comprising deoxygenated blood in the capillary, venular, and to a lesser extent, in the arteriolar compartments) instead of total CBV, and yet Delta CBVv measurements in humans have been extremely scarce. In this work, we demonstrate reproducible Delta CBVv measurements at 3 T using venous refocusing for the volume estimation (VERVE) technique, and report on steady-state Delta CBVv and ACBF measurements in human subjects undergoing graded visual and sensorimotor stimulation. We found that: (1) a BOLD-specific flow-volume power-law relationship is described by alpha = 0.23 +/- 0.05, significantly lower than Grubb's constant of 0.38 for total CBV, (2) this power-law constant was not found to vary significantly between the visual and sensorimotor areas; and (3) the use of Grubb's value of 0.38 in gradient-echo BOLD modeling results in an underestimation of Delta CMRo(2). Copyright (C) 2009 John Wiley & Sons, Ltd.