Measurement of brain oxygenation changes using dynamic T1-weighted imaging

Magnetic resonance imaging (MRI) has proven useful in evaluating oxygenation in several types of tissue and blood. This study evaluates brain tissue oxygenation changes between normoxia and hyperoxia in healthy subjects using dynamic T-1 and T-2*-weighted imaging sequences. The change in FiO2 induced by hyperoxia caused a significant decrease in T-1. A model to determine changes in tissue oxygen tension from the T-1-weighted MRI signal is presented based on previous findings that T-1 is sensitive to oxygen tension whereas T-2* is sensitive to blood saturation. The two sequences produce results with different regional and temporal dynamics. These differences combined with results from simulations of the T-1 signal intensities, indicate an increase in extravascular oxygen tension during hyperoxia. This study concludes that T-1 and T-2* responses to FiO2 serve as independent biomarkers of oxygen physiology in the brain with a potential to provide quantitative information on tissue oxygenation. (C) 2013 Elsevier Inc. All rights reserved.