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Changes in cerebral blood flow and cerebral oxygen metabolism during neural activation measured by positron emission tomography : comparison with changes in blood oxygeration level-dependent contrast measured by functional magnetic resonance imaging

正电子发射断层扫描测量神经激活过程中脑血流量和脑氧代谢的变化：与功能磁共振成像测量的血氧水平依赖性对比度变化的比较

基本信息

批准号：
15591314
负责人：
ITO Hiroshi
金额：
$ 1.54万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15591314/
关键词：
fMRI BOLD PET CBF CMRO2 OEF

项目摘要

The discrepancy between the increases in cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) during neural activation causes an increase in venous blood oxygenation and, therefore, a decrease in paramagnetic deoxyhemoglobin concentration in venous blood. This can be detected by functional magnetic resonance imaging (fMRI) as blood oxygenation level-dependent(BOLD) contrast. However, the relation between cerebral oxygen extraction fraction (OEF), that corresponds to the ratio of CMRO2 to CBF, and BOLD contrast duaring neural activation has not been shown directly in human subjects. In the present study, changes in the OEF and in the BOLD signal during neural activation were measured by both positron emission tomography (PET) and fMRI in the same human subjects. PET studies were performed in each of seven healthy men at rest (baseline) and during parformance of a right hand motor task fMRI studies were then performed to measure the BOLD signal under the two conditions. Regions of interest (ROIs) were defined on all CBF, cerebral blood volume (CBV), OEF, CMRO2, and BOLD images for areas showing statistically significant changes in CBF. Significant relatire hyperperfusion indicating neural activation during the motor task activity was observed in the left precentral gyrus, left superior frontal gyrus, right precentral gyrus, right cingulate gyrus, and right cerebellum. Significant relative hypoperfusion indicating neural deactivations during the motor task activity was observed in the left anterior part of cinglate gyrus and right occipital cuneus. A significant positive correlation was observed between changes in the CBF and the BOLD signal, and a significant negative correlation was observed between changes in the OEF and the BOLD signal for all ROIs. This supports the assumption on which BOLD contrast studies are based, that the discrepancy between increases in CBF and CMRO2 during neural activation causes an increase in venous blood oxygenation.

神经激活时脑血流量（CBF）的增加与脑氧代谢率（cmoo2）的增加之间的差异导致静脉血氧合增加，因此，静脉血中顺磁脱氧血红蛋白浓度降低。这可以通过功能性磁共振成像（fMRI）作为血氧水平依赖（BOLD）对比来检测。然而，在人类受试者中，神经激活期间脑氧提取分数（OEF），即cmor2与CBF的比值，与BOLD对比之间的关系尚未直接显示。在本研究中，通过正电子发射断层扫描（PET）和功能磁共振成像（fMRI）测量了同一受试者在神经激活过程中OEF和BOLD信号的变化。7名健康男性在休息时（基线）分别进行PET研究，并在执行右手运动任务时进行fMRI研究以测量两种情况下的BOLD信号。在所有CBF、脑血容量（CBV）、OEF、cmoro2和BOLD图像上定义感兴趣区域（roi），以确定CBF有统计学意义变化的区域。在运动任务活动中，左侧中央前回、左侧额上回、右侧中央前回、右侧扣带回和右侧小脑均观察到明显的相对高灌注，表明神经激活。在运动任务活动中，左扣带回前部和右枕楔叶观察到明显的相对灌注不足，表明神经失活。所有roi的CBF变化与BOLD信号呈显著正相关，OEF变化与BOLD信号呈显著负相关。这支持了BOLD对比研究所基于的假设，即神经激活期间CBF和cmor2增加之间的差异导致静脉血氧合增加。