Windowed stochastic proton decoupling for in vivo (13)C magnetic resonance spectroscopy with reduced RF power deposition.

PURPOSE

To propose a strategy for reducing radiofrequency (RF) power deposition by stochastic proton decoupling based on Rayleigh's theorem.

MATERIALS AND METHODS

Rayleigh's theorem was used to remove frequency components of stochastic decoupling over the 3.90-6.83 ppm range. [2-(13)C] or [2,5-(13) C(2) ]glucose was infused intravenously to anesthetized rats. (13)C labeling of brain metabolites was detected in the carboxylic/amide spectral region at 11.7 T using either the original stochastic decoupling method developed by Ernst or the proposed windowed stochastic decoupling method.

RESULTS

By restricting frequency components of stochastic decoupling to 1.91-3.90 ppm and 6.83-7.60 ppm spectral regions decoupling power deposition was reduced by ≈50%. The proposed windowed stochastic decoupling scheme is experimentally demonstrated for in vivo (13)C MRS of rat brain at 11.7 T.

CONCLUSION

The large reduction in decoupling power deposition makes it feasible to perform stochastic proton decoupling at very high magnetic fields for human brain (13)C MRS studies.