Edited MRS is sensitive to changes in lactate concentration during inspiratory hypoxia.

PURPOSE To demonstrate the application of Mescher-Garwood (MEGA) point-resolved spectroscopy sequence (PRESS) editing to the detection of lactate in the brain at 3T and to investigate changes in lactate concentration associated with inspiratory gas challenges. MATERIALS AND METHODS Edited lactate measurements were made in six healthy volunteers while the subjects breathed normoxic (21% O(2)), hypoxic (12% O(2)), and hyperoxic (40% O(2)) gas mixtures. Lactate concentration was quantified relative to the unsuppressed water signal from the same volume. RESULTS Lactate concentration was elevated in all subjects during hypoxia in a highly significant fashion (mean increase = 39%; P = 0.0003). There was no significant change seen in hyperoxia. CONCLUSION MEGA-PRESS editing at 3T is sufficiently sensitive to detect lactate in the healthy brain with good signal-to-noise ratio (SNR), and can be used to investigate changes in cerebral metabolism arising during inspiratory gas challenges.