BROAD-BAND DECOUPLED, H-1-LOCALIZED C-13 MRS OF THE HUMAN BRAIN AT 4 TESLA

Broadband proton decoupling of the entire C-13 spectrum was possible w ithin power absorption guidelines and resulted in the detection of nar row (as low as 2-3 Hz), natural abundance signals from metabolites suc h as myo-inositol, glutamate, N-acetyl-aspartate, and glutamine from 7 2 cm(3) volumes in the human brain. To overcome the chemical shift dis placement error, three-dimensional localization on the H-1 z magnetiza tion was combined with polarization transfer. Efficiency of the hetero nuclear localization method was demonstrated by the elimination of all scalp lipid resonances. A signal-to-noise ratio of 5:1 for 0.07 mM [C -13] was achieved in 12 min, which is approximately a fivefold improve ment over the sensitivity reported at 2.1 Tesla.