Bulte Daniel P, Chiarelli Peter A, Wise Richard G, Jezzard Peter
FMRIB Centre, Department of Clinical Neurology, University of Oxford, Oxford, UK.
J Cereb Blood Flow Metab. 2007 Jan;27(1):69-75. doi: 10.1038/sj.jcbfm.9600319. Epub 2006 May 3.
Graded levels of supplemental inspired oxygen were investigated for their viability as a noninvasive method of obtaining intravascular magnetic resonance image contrast. Administered hyperoxia has been shown to be effective as a blood oxygenation level-dependent contrast agent for magnetic resonance imaging (MRI); however, it is known that high levels of inspired fraction of oxygen result in regionally decreased perfusion in the brain potentially confounding the possibility of using hyperoxia as a means of measuring blood flow and volume. Although the effects of hypoxia on blood flow have been extensively studied, the hyperoxic regime between normoxia and 100% inspired oxygen has been only intermittently studied. Subjects were studied at four levels of hyperoxia induced during a single session while perfusion was measured using arterial spin labelling MRI. Reductions in regional perfusion of grey matter were found to occur even at moderate levels of hyperoxia; however, perfusion changes at all oxygen levels were relatively mild (less than 10%) supporting the viability of hyperoxia-induced contrast.
研究了分级补充吸入氧气作为一种获取血管内磁共振图像对比度的非侵入性方法的可行性。已证明给予高氧作为磁共振成像（MRI）的血氧水平依赖性造影剂是有效的；然而，已知高氧吸入分数会导致大脑局部灌注减少，这可能会混淆使用高氧作为测量血流和血容量手段的可能性。尽管缺氧对血流的影响已得到广泛研究，但常氧和100%吸入氧气之间的高氧状态仅得到间歇性研究。在单次实验中，对受试者在四个高氧水平下进行研究，同时使用动脉自旋标记MRI测量灌注。发现即使在中度高氧水平下，灰质的局部灌注也会降低；然而，所有氧水平下的灌注变化相对较小（小于10%），这支持了高氧诱导对比度的可行性。
