Calibrated functional MRI: Mapping the dynamics of oxidative metabolism
Calibrated functional MRI: Mapping the dynamics of oxidative metabolism
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DOI：
10.1073/pnas.95.4.1834
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发表时间：
1998-02-17
影响因子：
11.1
通讯作者：
Rosen, BR
中科院分区：
文献类型：
--
作者：
Davis, TL;Kwong, KK;Rosen, BR
MRI 扩展到测量正常人在功能诱导的细胞活动变化过程中氧化代谢的变化。一种与模型无关的无创 MRI 方法，使用二氧化碳呼吸作为生理参考标准，根据灌注敏感 MRI 校准功能 MRI (fMRI) 的血氧水平依赖性 (BOLD) 信号。该校准程序提供了 fMRI BOLD 信号对大脑细胞活动变化的预期敏感性的区域测量。 BOLD 信号校准因子图显示 ed 区域异质性，表明 BOLD 信号中功能性诱导变化的幅度将取决于血流的局部变化和大脑皮层的局部基线生理学，BOLD 信号幅度显示由于氧代谢的作用而比预期水平降低了 32%，校准后的 fMRI 技术应用于以交替径向棋盘图案刺激人类视觉皮层，这种刺激耗氧量增加了 16%，而血流量增加45%。尽管这一结果与之前的血流量增加和耗氧量增加之间存在显着差异的发现一致，但它确实清楚地表明，氧化代谢是大脑对功能性诱导的细胞活动变化的代谢反应的重要组成部分。
MRI was extended to the measurement of changes in oxidative metabolism in the normal human during functionally induced changes in cellular activity, A noninvasive MRI method that is model-independent calibrates the blood oxygen level dependent (BOLD) signal of functional MRI (fMRI) against perfusion-sensitive MRI, using carbon dioxide breathing as a physiological reference standard, This calibration procedure provides a regional measurement of the expected sensitivity of the fMRI BOLD signal to changes in the cellular activity of the brain. Maps of the BOLD signal calibration factor show ed regional heterogeneity, indicating that the magnitude of functionally induced changes in the BOLD signal will be dependent on both the local change in blood flow and the local baseline physiology of the cerebral cortex, BOLD signal magnitude is shown to be reduced by 32% from its expected level by the action of oxygen metabolism, The calibrated fMRI technique was applied to stimulation of the human visual cortex with an alternating radial checkerboard pattern, With this stimulus oxygen consumption increased 16% whereas blood flow increased 45%. Although this result is consistent with previous findings of a significant difference between the increase in blood flow and oxygen consumption, it does indicate clearly that oxidative metabolism is a significant component of the metabolic response of the brain to functionally induced changes in cellular activity.