Li T Q, Kastrup A, Moseley M E, Glover G H
Department of Diagnostic Radiology, Lucas MR Imaging and Spectroscopy Center, Stanford University School of Medicine, Stanford, California 94305-5488, USA.
J Magn Reson Imaging. 2000 Nov;12(5):757-62. doi: 10.1002/1522-2586(200011)12:5<757::aid-jmri14>3.0.co;2-4.
The effect of changes in baseline regional cerebral blood flow (rCBF) values on the cerebral blood flow response during neuronal activation was studied with functional magnetic resonance imaging (fMRI). Using a breath-holding challenge as a hypercapnic stimulus, rCBF alterations during photic stimulation under normo- and hypercapnia were determined in nine volunteers. With breath-holding, baseline rCBF in areas corresponding to the visual cortex significantly increased from 54 +/- 5 ml/100 g/min to 85 +/- 9 ml/100 g/min (P < 0.001). Despite this significant change in baseline flow values, the rCBF increase during visual stimulation was very similar under normo- and hypercapnic conditions (28 +/- 8 ml/100 g/min versus 26 +/- 8 ml/100 g/min, respectively). This study supports the notion that within wide physiologic variations, task-induced cerebral blood flow changes are independent of baseline rCBF values.
采用功能磁共振成像（fMRI）研究了基线局部脑血流量（rCBF）值的变化对神经元激活期间脑血流反应的影响。以屏气挑战作为高碳酸血症刺激，在9名志愿者中测定了正常碳酸血症和高碳酸血症状态下光刺激期间的rCBF变化。屏气时，对应于视觉皮层区域的基线rCBF从54±5 ml/100 g/min显著增加至85±9 ml/100 g/min（P<0.001）。尽管基线血流值有这一显著变化，但在正常碳酸血症和高碳酸血症条件下，视觉刺激期间的rCBF增加非常相似（分别为28±8 ml/100 g/min和26±8 ml/100 g/min）。本研究支持以下观点：在广泛的生理变化范围内，任务诱导的脑血流变化与基线rCBF值无关。
