Retaining Polarization by Exploiting Reduced T1 Relaxation of Hyperpolarized Spins at Low Field in Solution

Mark Van Criekinge¹, Kayvan R. Keshari, Daniel Vigneron, John Kurhanewicz

An important consideration for performing hyperpolarized (HP) 13C-MR studies is matching the T1 relaxation time of the HP 13C-labeled probe with the time scale of the metabolic process being investigated. By evolving the hyperpolarized spins in low field (<0.1T), a dramatic increase in [1-13C]pyruvate relaxation rate was indirectly observed as a 50% increase in residual polarization. For in vivo studies, it is possible that hyperpolarized spins could be allowed to evolve inside of animals at low field, in the fringe field of the magnet, and subsequently transport them into the magnet at a later time to observe slower enzyme kinetics.