DYNAMIC C-13-H-1 NUCLEAR-POLARIZATION OF LIPID METHYLENE RESONANCES APPLIED TO BROAD-BAND PROTON-DECOUPLED IN-VIVO C-13 MR SPECTROSCOPY OF HUMAN BREAST AND CALF TISSUE
G. Ende et P. Bachert, DYNAMIC C-13-H-1 NUCLEAR-POLARIZATION OF LIPID METHYLENE RESONANCES APPLIED TO BROAD-BAND PROTON-DECOUPLED IN-VIVO C-13 MR SPECTROSCOPY OF HUMAN BREAST AND CALF TISSUE, Magnetic resonance in medicine, 30(4), 1993, pp. 415-423
Dynamic nuclear polarization of the coupled C-13-H-1 spin system was s
tudied for optimizing the signal-to-noise ratio of in vivo C-13 MR spe
ctra. In particular, the truncated driven and transient nuclear Overha
user effect (NOE) of the proton-decoupled C-13 resonances from methyle
ne carbons in vegetable oil and in human calf tissue was observed. Max
imum in vivo NOE enhancements eta = 1.5 and 0.9 were found, respective
ly. Theoretical fits to the data yield C-13-H-1 cross-relaxation times
in the order of 0.6 s. Significant signal enhancement over the whole
in vivo C-13 chemical shift range is obtained with minimum expense uti
lizing the NOE of the dipolar coupled C-13-H-1 spin system in addition
to proton-decoupling. NOE-enhanced proton-decoupled in vivo C-13 MR s
pectra were acquired within 17 min in volunteer examinations from the
human breast and the calf. These spectra show well-resolved resonances
of carbons in lipids and several other cellular compounds.