title: Cerebral perfusion response to hyperoxia.
abstract: 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.
authors: FMRIB Centre, Department of Clinical Neurology, University of Oxford, Oxford, UK. bulte@fmrib.ox.ac.uk
authors: Daniel P
authors: DP
authors: Bulte
authors: Peter A
authors: PA
authors: Chiarelli
authors: Richard G
authors: RG
authors: Wise
authors: Peter
authors: P
authors: Jezzard