Clinical-Scale Batch-Mode Production of Hyperpolarized Propane Gas for MRI

NMR spectroscopy and imaging (MRI) are two of the most important methods to study structure, function and dynamics from atom to organism scale. NMR approaches often suffer from an insufficient sensitivity, which, however, can be transiently boosted using hyperpolarization techniques. One of these techniques is parahydrogen-induced polarization which has been used to produce catalyst-free hyperpolarized propane gas with proton polarization that is three orders of magnitude greater than equilibrium thermal polarization at a 1.5 T field of a clinical MRI scanner. Here we show that more than 0.3 liters of hyperpolarized propane gas can be produced in 2 seconds. This production rate is more than an order of magnitude greater than that demonstrated previously, and the reported production rate is comparable to that employed for in-human MRI using HP noble gas (e.g. 129Xe) produced via Spin Exchange Optical Pumping (SEOP) hyperpolarization technique. We show that high polarization values can be retained despite the significant increase in the production rate of hyperpolarized propane. The enhanced signals of produced hyperpolarized propane gas were revealed by stopped-flow MRI visualization at 4.7 T. Achieving this high production rate enables the future use of this already compound (already approved for unlimited use in foods by the corresponding regulating agencies, e.g. FDA in the USA, and more broadly as E944 food additive) as a new inhalable contrast agent for diagnostic detection via MRI.