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Abstract

Introduction: Over the last century, advances in Magnetic Resonance (MR) technologies have revolutionized modern science and technology. Despite the tremendous progress, typical MR experiments only measure a tiny fraction of the available nuclear spins in samples. In this contribution we present particularly simple-to-implement parahydrogen-based hyperpolarization chemistry to boost NMR and MRI signals by several orders of magnitude. Such technology is intriguing because unexplored opportunities and new physical effects arise. Aims: The presented work aims for (A) scalable molecular imaging via low-field hyperpolarized MRI, which can be made broadly available and for (B) precision NMR via the parahydrogen pumped RASER (Radiofrequency Amplification by Stimulated Emission of Radiation). Methods: (A) We advance parahydrogen-based Signal Amplification By Reversible Exchange (SABRE) to hyperpolarize a wide range of molecules and process them into a biocompatible solution, which is injected into rodents at low magnetic fields to observe metabolism non-invasively. (B) We use both hydrogenative parahydrogen induced polarization (PHIP) and SABRE to attain polarization levels that exceed the RASER threshold to yield everlasting NMR signal associated with unprecedented precision. Results: (A) In vivo hyperpolarized NMR and MRI are enabled to observe metabolic conversion of pyruvate to alanine, lactate and bicarbonate in liver and kidney at 1.5 T magnetic fields. In phantom hyperpolarized MRI of 13C pyruvate is shown all the way down to 120 uT. (B) parahydrogen pumped RASER NMR is demonstrated for both 1H and 13C systems showcasing more than 100-fold improvements in resolution over conventional NMR while retaining the critical J- coupling and chemical shift information. Conclusion: This contribution illustrates how detailed, fundamental spin physics and chemistry can be translated to major advances, with a keen eye on making modern technology broadly available and providing affordable tools that give the most precise information possible.