Refocused double‐quantum editing for lactate detection at 7 T

Lactate is an important marker for anaerobic glucose metabolism, and it is therefore of particular interest in, for example, cerebral ischemia, skeletal muscle disorders, and in the monitoring of oncology treatments. However, the in vivo detection of lactate with magnetic resonance spectroscopy is complicated by the overlap of the low‐intensity lactate methyl resonance with lipid signal. Therefore, double‐quantum filters have been employed to dephase the overlapping lipid signal, as they allow for a very high lipid suppression efficiency. For reliable lactate detection in lipid‐rich environment, very large crushing gradients have to be employed to dephase the lipid signal under the noise level. Double‐quantum filters are generally associated with signal loss of the metabolite of interest. For lactate, half of the signal is lost by selecting either the double‐ or the zero‐quantum coherences. Moreover, owing to incomplete refocusing, traditional double‐quantum filters with very large crusher gradients exhibit additional loss of the already low‐lactate signal. In this study, a refocused double‐quantum filter is described, which does not suffer from this source of additional signal loss. Therefore, it becomes possible to detect lactate at lower concentrations, or in lipid‐rich environments. Lactate measurements are shown in the human calf muscle at 7 T. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.