Basal cerebral blood volume during the poststimulation undershoot in BOLD MRI of the human brain
Basal cerebral blood volume during the poststimulation undershoot in BOLD MRI of the human brain
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DOI：
10.1038/jcbfm.2010.133
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发表时间：
2011-01-01
影响因子：
6.3
通讯作者：
Frahm, Jens
中科院分区：
文献类型：
--
作者：
Dechent, Peter;Schuetze, Gunther;Frahm, Jens
血氧水平依赖性（BOLD）磁共振成像（MRI）对大脑功能挑战的反应的特征之一是刺激后下冲，这被认为源于脑血容量（CBV）或脑氧代谢率恢复到基线的延迟。最近，我们在人体中使用推注跟踪 MRI，发现相对 CBV 在刺激结束后迅速恢复正常。由于这一观察结果至少与在动物身上进行的血池造影剂研究的一部分相矛盾，我们通过动态 T1 加权三维 MRI（8 秒时间分辨率）和 3T 的 Vasovist（12 名受试者）重新研究了 CBV 的贡献。最初，我们确定了各个 BOLD 响应的时间常数。注射 Vasovist 后，CBV 相关的 T1 加权信号变化显示视觉刺激期间信号增加 (1.7% +/- 0.4%)，但在刺激后阶段相对于基线没有变化 (0.2% +/- 0.3%)。这一发现表明造影剂的具体性质不太可能造成人类和动物研究之间的差异。假设刺激停止后脑血流量正常化，正常化的 CBV 支持以下观点：BOLD MRI 下冲反映了氧化代谢的长期升高。脑血流与代谢杂志 (2011) 31, 82-89; doi：10.1038/jcbfm.2010.133； 2010 年 8 月 25 日在线发布
One of the characteristics of the blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) response to functional challenges of the brain is the poststimulation undershoot, which has been suggested to originate from a delayed recovery of either cerebral blood volume (CBV) or cerebral metabolic rate of oxygen to baseline. Using bolus-tracking MRI in humans, we recently showed that relative CBV rapidly normalizes after the end of stimulation. As this observation contradicts at least part of the blood-pool contrast agent studies performed in animals, we reinvestigated the CBV contribution by dynamic T1-weighted three-dimensional MRI (8 seconds temporal resolution) and Vasovist at 3T (12 subjects). Initially, we determined the time constants of individual BOLD responses. After injection of Vasovist, CBV-related T1-weighted signal changes revealed a signal increase during visual stimulation (1.7% +/- 0.4%), but no change relative to baseline in the poststimulation phase (0.2% +/- 0.3%). This finding renders the specific nature of the contrast agent unlikely to be responsible for the discrepancy between human and animal studies. With the assumption of normalized cerebral blood flow after stimulus cessation, a normalized CBV lends support to the idea that the BOLD MRI undershoot reflects a prolonged elevation of oxidative metabolism. Journal of Cerebral Blood Flow & Metabolism (2011) 31, 82-89; doi:10.1038/jcbfm.2010.133; published online 25 August 2010