Impact of sub-echo timings of PRESS on quantitative glutamate/glutamine level using LCModel at 7T

In this study, we investigated the signal variation of Glu and Gln along sub-echo timings (TE1, TE2) in PRESS acquisitions on a preclinical 7T system. Our results show that the choice of sub-echo timings (TE1, TE2) for PRESS may alter the quantitative outcome remarkably for strongly coupled metabolites, e.g. Glu, Gln. The basis-sets used for LCModel analysis has to be carefully simulated and take the sub-echo timings into account since J-evolution of strongly coupled resonances may vary with TE1/TE2 at high fields. Quantitative comparison on these metabolites with mismatched sub-echo timings (TE1, TE2) can result in invalid conclusion.