Broadband decoupled, ¹H-localized ¹³C MRS of the human brain at 4 Tesla

Broadband proton decoupling of the entire ¹³C spectrum was possible within power absorption guidelines and resulted in the detection of narrow (as low as 2-3 Hz), natural abundance signals from metabolites such as myo- inositol, glutamate, N-acetyl-aspartate, and glutamine from 72 cm³ volumes in the human brain. To overcome the chemical shift displacement error, three- dimensional localization on the ¹H z magnetization was combined with polarization transfer. Efficiency of the heteronuclear localization method was demonstrated by the elimination of all scalp lipid resonances. A signal- to-noise ratio of 5:1 for 0.07 mM [¹³C] was achieved in 12 min, which is approximately a fivefold improvement over the sensitivity reported at 2.1 Tesla.