Improvements in Spectral Resolution in in vivo-Hyperpolarized 13C-CSI on Pigs Using Spectroscopic GRASE
Wieben O, Mansson S, Leupold J, Petersson J, Hennig J
Hyperpolarized 13C shows in vivo relaxation rates in the range of 30-60 s. This allows to observe rapid metabolic turnover after injection of suitable substrates like 13C-pyruvate. In order to maximize spatial and spectral resolution a spectroscopic GRASE-sequence with 13 echoes within each refocusing period was used for data acquisition. The spectral resolution is in the same order as the peak separation, therefore direct Fourier Transformation leads to severe spectral degradation by partial volume effects. These can be remedied by sinc-interpolation leading to significant improvements of spectral amplitude, resolution and peak definition. Equivalence between superresolution reconstruction, frequency sweep reconstruction and sinc-interpolation is discussed.