In Vivo Metabolic Imaging of [1-13C]Pyruvate-d3 Hyperpolarized By Reversible Exchange With Parahydrogen

Metabolic magnetic resonance imaging (MRI) using hyperpolarized (HP) pyruvate has shown promise as a non-invasive technique for diagnosing, staging, and monitoring response to treatment in cancer and other diseases. The clinically established method for producing HP pyruvate is dynamic nuclear polarization; however, it is rather expensive and slow. Here, we demonstrate fast (6 min), low-cost production of HP [1-13C]pyruvate-d3 in aqueous solution using Signal Amplification By Reversible Exchange (SABRE), and in vivo metabolic MRI. The injected solution was sterile, non-toxic, pH neutral and contained ≈30 mM [1-13C]pyruvate-d3 polarized to ≈11% (residual 250 mM methanol and 20 µM catalyst). It was obtained by rapid solvent evaporation and metal filtering. The procedure was well tolerated by all four mice studied here. This achievement is a significant step of making HP MRI available to a wider community. Fast, low-cost, and high-throughput parahydrogen-hyperpolarization has become a viable alternative for metabolic MRI of living organisms.