Introduction MRI (magnetic resonance imaging) is a powerful, noninvasive medical technique, but has limitations due to the intrinsic low sensitivity. To overcome this problem, it is possible to hyperpolarize the nuclear spins, a procedure that has been shown to produce signal enhancements of biomolecules up to 10 5 at high field . Unfortunately, the hyperpolarization decays in (typically) tens of seconds due to spin relaxation. Despite this temporal limitation, it is possible to observe real-time cellular metabolism in vitro and in vivo after injection of hyperpolarized metabolites .