Resolution Enhancement of Brain Glutamate, Glutamine and myo-Inositol by PRESS (TE1, TE2) = (37, 63) ms at 7T

INTRODUCTION At high fields, although the resolution between singlets may remain the same, the selectivity of coupled resonances is enhanced because the coupling strength which governs the overall linewidth of the multiplet is independent of field strength (B0). Short echo time (TE) acquisition benefits from the reduced T2 signal loss, but the increased macromolecule (MM) baseline signals complicate the spectral analysis. Alternatively, long TE acquisition can be employed with an advantage that TE optimization provides improved selectivity of target metabolites and suppresses the MM signals to noise level. Given that PRESS (point-resolved spectroscopy) and STEAM (stimulated-echo acquisition mode) sequences are readily available in most of the clinical MR scanners, a strategy for selectivity enhancement of experimentallychallenging metabolites using these methods would be valuable. Here, we report PRESS echo time optimization for precise detection of glutamate (Glu), glutamine (Gln) and myo-inositol (mI) in human brain at 7T.