D2O vs H2O Dissolutions for Enhancing Human MR Imaging of Hyperpolarized [2-13C]Pyruvate Conversions to Glutamate and Lactate

Motivation: Hyperpolarized [2-13C]pyruvate for MR metabolic imaging has low SNR due to shorter T1 in H2O compared to [1-13C]pyruvate. Dissolving in D2O can enhance T1 and SNR. Goal(s): We aimed to increase T1 for hyperpolarized [2-13C]pyruvate in-vivo studies using D2O dissolutions to improve metabolic imaging of brain glycolysis and oxidative metabolism. Approach: T1 and polarization levels of hyperpolarized [2-13C]pyruvate, produced for human studies in H2O or D2O, were analyzed using NMR spectroscopy. Results: Dissolving hyperpolarized [2-13C]pyruvate in D2O increased T1 by 1.4-fold and polarization by a 1.8-fold after ~2 minutes in vitro, with in-vivo brain data, indicating potential for better imaging quality. Impact: Dissolving hyperpolarized [2-13C]pyruvate in D2O instead of H2O increased T1, yielding higher polarization for human MRI studies. This approach is expected to improve the quality of hyperpolarized [2-13C]pyruvate MRI, enabling more accurate assessments of oxidative & glycolytic metabolism of pyruvate.