Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen , Denmark.
Functional Imaging Unit, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Glostrup, Denmark.
J Appl Physiol (1985). 2018 Oct 1;125(4):1080-1089. doi: 10.1152/japplphysiol.00276.2018. Epub 2018 Jul 5.
Studies of the resting brain measurements of cerebral blood flow (CBF) show large interindividual and regional variability, but the metabolic basis of this variability is not fully established. The aim of the present study was to reassess regional and interindividual relationships between cerebral perfusion and glucose metabolism in the resting brain. Regional quantitative measurements of CBF and cerebral metabolic rate of glucose (CMR) were obtained in 24 healthy young men using dynamic [O]HO and [F]fluorodeoxyglucose positron emission tomography (PET). Magnetic resonance imaging measurements of global oxygen extraction fraction (gOEF) and metabolic rate of oxygen ([Formula: see text]) were obtained by combined susceptometry-based sagittal sinus oximetry and phase contrast mapping. No significant interindividual associations between global CBF, global CMR, and [Formula: see text] were observed. Linear mixed-model analysis showed a highly significant association of CBF with CMR regionally. Compared with neocortex significantly higher CBF values than explained by CMR were demonstrated in infratentorial structures, thalami, and mesial temporal cortex, and lower values were found in the striatum and cerebral white matter. The present study shows that absolute quantitative global CBF measurements appear not to be a valid surrogate measure of global cerebral glucose or oxygen consumption, and further demonstrates regionally variable relationship between perfusion and glucose metabolism in the resting brain that could suggest regional differences in energy substrate metabolism. NEW & NOTEWORTHY Using method-independent techniques the study cannot confirm direct interindividual correlations of absolute global values of perfusion with oxygen or glucose metabolism in the resting brain, and absolute global perfusion measurements appear not to be valid surrogate measures of cerebral metabolism. The ratio of both perfusion and oxygen delivery to glucose metabolism varies regionally, also when accounting for known methodological regional bias in quantification of glucose metabolism.
研究静息状态下大脑的脑血流（CBF）测量结果表明，个体间和区域间存在很大的变异性，但这种变异性的代谢基础尚未完全确定。本研究旨在重新评估静息状态下大脑灌注和葡萄糖代谢的区域和个体间关系。使用动态[O]HO 和 [F]氟脱氧葡萄糖正电子发射断层扫描（PET）对 24 名健康年轻男性进行了 CBF 和大脑葡萄糖代谢率（CMR）的区域定量测量。通过基于磁化率的矢状窦血氧饱和度和相位对比映射联合测量，获得了全局氧摄取分数（gOEF）和氧代谢率（[Formula: see text]）的磁共振成像测量值。未观察到全局 CBF、全局 CMR 和 [Formula: see text] 之间存在显著的个体间相关性。线性混合模型分析显示 CBF 与 CMR 之间存在显著的区域相关性。与皮质相比，在小脑幕下结构、丘脑和内侧颞叶中发现了明显高于 CMR 解释的 CBF 值，而在纹状体和大脑白质中则发现了较低的 CBF 值。本研究表明，绝对定量的全局 CBF 测量值似乎不能作为全局脑葡萄糖或耗氧量的有效替代测量值，并且进一步证明了静息状态下大脑中灌注和葡萄糖代谢之间存在区域变化的关系，这可能表明能量底物代谢存在区域差异。本研究使用方法独立的技术，不能证实静息状态下大脑的绝对全局灌注值与氧或葡萄糖代谢之间的直接个体间相关性，并且绝对全局灌注测量值似乎不能作为大脑代谢的有效替代测量值。在考虑到葡萄糖代谢定量的已知方法学区域偏差时，灌注和氧气输送与葡萄糖代谢的比值在区域上也存在差异。
