In vivo hyperpolarized 13C MR spectroscopic imaging with 1H decoupling

Application of 13C MRS in vivo on whole body MR system has been limited due to the low static field (and consequent low signal to noise ratio-SNR) of these scanners; thus there have been few reports of 1H decoupled 13C MRS in vivo using a clinical MR platform. The recent development of techniques to retain highly polarized spins in solution following DNP in a solid matrix has provided a mechanism to use endogenous pre-polarized 13C labeled substrates to study real time cellular metabolism in vivo with high SNR. In a recent in vivo hyperpolarized metabolic imaging study using 13C pyruvate, it has been demonstrated that the line shape (signal decay) of the resonances observed are greatly affected by JCH coupling in addition to inhomogeneous broadening. This study demonstrates the feasibility of improving hyperpolarized 13C metabolic imaging in vivo by incorporating 1H decoupling on a clinical whole body 3 T MR scanner. No reduction of T1 of a pre-polarized 13C substrate ([1-13C] lactate) in solution was observed when 1H decoupling was applied with WALTZ16 sequence. Narrower linewidth for the [1-13C] lactate resonance was observed in hyperpolarized 13C MRSI data in vivo with 1H decoupling.