Over 20% 13C Hyperpolarization for Pyruvate Using Deuteration and Rapid SLIC-SABRE in Mictrotesla Fields

Carbon-13 hyperpolarized pyruvate is about to become the next-generation contrast agent for molecular magnetic resonance imaging of cancer and other diseases. Here, efficient and rapid pyruvate hyperpolarization is achieved via Signal Amplification by Reversible Exchange (SABRE) with parahydrogen through synergistic use of substrate deuteration, alternating, and static microtesla magnetic fields. Up to 22% and 6% long-lasting 13C polarization (T1=3.7±0.25min and T1=1.7±0.1min) is demonstrated for the C1 and C2 nuclear sites, respectively. The remarkable polarization levels become possible due to favorable relaxation dynamics at the microtesla fields. The ultra-long polarization lifetimes will be conducive to yielding high polarization after purification, quality assurance, and injection of the hyperpolarized molecular imaging probes. These results pave the way to future in vivo translation of carbon-13 hyperpolarized molecular imaging probes prepared by this approach.