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The signal enhancement provided by the hyperpolarization of nuclear spins of metabolites is a promising technique for diagnostic magnetic resonance imaging (MRI). To date, most 13 C-contrast agents are hyperpolarized utilizing a complex or cost-intensive polarizer. Recently, the in situ para hydrogen-induced 13 C hyperpolarization was demonstrated. Hydrogenation, spin order transfer (SOT) by a pulsed NMR sequence, in vivo administration, and detection was achieved within the magnet bore of a 7 Tesla MRI system. So far, the hyperpolarization of the xenobiotic molecule 1- 13 C-hydroxyethylpropionate (HEP) and the biomolecule 1- 13 C-succinate (SUC) through the PH-INEPT+ sequence and a SOT scheme proposed by Goldman et al. , respectively, was shown. Here, we investigate further the hyperpolarization of SUC at 7 Tesla and study the performance of two additional SOT sequences. Moreover, we present first results of the hyperpolarization at high magnetic field of 1- 13 C-phospholactate (PLAC), a derivate to obtain the metabolite lactate, employing the PH-INEPT+ sequence. For SUC and PLAC, 13 C polarizations of about 1–2% were achieved within seconds and with minimal equipment. Effects that potentially may explain loss of 13 C polarization have been identified, i.e. low hydrogenation yield, fast T 1 / T 2 relaxation and the rarely considered 13 C isotope labeling effect. 

Abstract Metabolic magnetic resonance imaging (MRI) using hyperpolarized (HP) pyruvate is becoming 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, dissolution dynamic nuclear polarization, however, is rather complex and slow. Signal Amplification By Reversible Exchange (SABRE) is an ultra‐fast and low‐cost method based on fast chemical exchange. Here, for the first time, we demonstrate not only in vivo utility, but also metabolic MRI with SABRE. We present a novel routine to produce aqueous HP [1‐¹³C]pyruvate‐d₃for injection in 6 minutes. The injected solution was sterile, non‐toxic, pH neutral and contained ≈30 mM [1‐¹³C]pyruvate‐d₃polarized to ≈11 % (residual 250 mM methanol and 20 μM catalyst). It was obtained by rapid solvent evaporation and metal filtering, which we detail in this manuscript. This achievement makes HP pyruvate MRI available to a wide biomedical community for fast metabolic imaging of living organisms.