The MEGA-PRESS sequence has been widely used to measure the δH 3.02 γ-amino butyric acid (GABA) signal by J-difference editing. However, the sequence cannot eliminate the macromolecule signals at the same chemical shift completely. Symmetrical editing can be applied to suppress the macromolecule signals. However, the approach is rarely applied at field strength of 3 T due to insufficient frequency selectivity of the editing pulse. In this study, GABA+(i.e., GABA+macromolecules) and macromolecule-suppressed GABA signals in the occipital lobe of human subjects were measured with symmetrical editing at 3 T. The duration of the editing pulse was increased from 14 ms to 20 ms to improve frequency selectivity, and echo time (TE) from 68 ms to 80 ms. It was found that the fraction of the total signal retained following macromolecule suppression ([GABA]/[GABA+]) was 0.73. It is concluded that symmetric macromoleculesuppressed editing can be used to acquire macromolecule-suppressed GABA signals, and may serve as a better tool to assess inter-individual differences in cerebral GABA level.
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