Quantification of cortical GABA-glutamine cycling rate using in vivo magnetic resonance signal of [2-13C]GABA derived from glia-specific substrate [2-13C]acetate.

Brain [2-(13)C]gamma-aminobutyric acid (GABA) signal derived from the glia-specific substrate [2-(13)C]acetate reflects the extent of the GABA-glutamine neurotransmitter cycling between GABAergic neurons and glial cells. We report, for the first time, in vivo quantification of the GABA-glutamine cycling flux. The GABA-glutamine cycling flux rate was determined to be 1.

A new strategy for in vivo spectral editing. Application to GABA editing using selective homonuclear polarization transfer spectroscopy.

A novel single-shot in vivo spectral editing method is proposed in which the signal to be detected, is regenerated anew from the thermal equilibrium magnetization of a source to which it is J-coupled. The thermal equilibrium magnetization of the signal to be detected together with those of overlapping signals are suppressed by single-shot gradient dephasing prior to the signal regeneration process. Application of this new strategy to in vivo GABA editing using selective homonuclear polarization transfer allows complete suppression of overlapping creatine and glutathione while detecting the GABA-4 methylene resonance at 3.

Measurement and automatic correction of high-order B0 inhomogeneity in the rat brain at 11.7 Tesla.

In vivo B(0) inhomogeneity in the rat brain at 11.7 Tesla was measured and decomposed up to the fourth-order spherical harmonic terms using an automatic slice shimming routine derived from the FLATNESS method. In vivo shimming of horizontal slices showed that significant improvement in the T(2)*-weighted echo-planar imaging was achieved after correction of all first-, second- and third-order in-slice shims.