Ovidiu C. Andronesi1, Aaron T. Hess2, Matthew Dylan Tisdall1, Wolfgang Bogner1, Andr J. W. van der Kouwe1, Bruce R. Rosen1
1Martinos Center, Radiology, Massachusetts General Hospital, Charlestown, MA, United States; 2Centre for Clinical Magnetic Resonance, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
J-difference spectral editing sequences such are necessary to detect important neurotransmitters and brain metabolites such as GABA, glutamate, 2-hydroxyglutarate, and glutathione which are otherwise obscured by more stronger signals. However, difference methods are susceptible to subtraction artifacts caused by subject movement, while the performance of narrow band MEGA pulses may be affected by drifts in the B0 field and shims. These challenges are likely to happen because editing requires long measurement times. Here we show that by acquiring in each TR an EPI volume navigator of the whole head prior to MEGA-LASER excitation we can perform real-time correction of motion in human subjects and update the shims and scanner frequency.