Chen, A.P. and C.H. Cunningham, Single voxel localization for dynamic hyperpolarized 13C MR spectroscopy. J. Magn. Reson., 2015. 258: p. 81-85.
The PRESS technique has been widely used to achieve voxel localization for in vivo 1H MRS acquisitions. However, for dynamic hyperpolarized 13C MRS experiments, the transition bands of the refocusing pulses may saturate the pre-polarized substrate spins flowing into the voxel. This limitation may be overcome by designing refocusing pulses that do not perturb the resonance of the hyperpolarized substrate, but selectively refocuses the spins of the metabolic products. In this study, a PRESS pulse sequence incorporating spectral–spatial refocusing pulses that have a stop band (‘notch’) at the substrate resonance is tested in vivo using hyperpolarized [1-13C]pyruvate. Higher metabolite SNR was observed in experiments using the spectral–spatial refocusing pulses as compared to conventional refocusing pulses.