Neurotransmitter profiling at 3T using GABA optimized PRESS sequence

Introduction: GABA is the major inhibitory neurotransmitter in mammalian brain and GABAergic alterations have been implicated in several psychiatric and neurological disorders. GABA was also proposed to underlie DFM modulation (1). Because of this growing interest in understanding physiology and pathophaysiology of cerebral GABA homeostasis, there is a need for robust measurement of in vivo GABA levels. On the other hand, spectroscopic detection of GABA is still challenging due to its low concentration, and the fact that all GABA peaks are overlapped by much stronger metabolite resonances at the field strength accessible for clinical studies. Our aim is to simultaneously detect GABA as well as Glu, Gln using a standard PRESS localization pulse sequence with optimized timing parameters. This approach exploits the dependence of the spectra of the strongly coupled spin systems on the partial echo times TE1 and TE2 at 3 T to find an optimized sequence parameter set {TE1, TE2} (2).