Signal Amplification by Reversible Exchange (SABRE)::From Discovery to Diagnosis

Signal Amplification by Reversible Exchange (SABRE) turns typically weak magnetic resonance responses into strong signals making previously impractical measurements possible. This technique has gained significant popularity due to its speed and simplicity. This minireview tracks the development of SABRE from the initial hyperpolarization of pyridine in 2009, to the point where 50% 1H polarization levels have be achieved in a di-deuterio-nicotinate, a key step in the pathway to potential clinical use. Simple routes to highly efficient 15N hyperpolarization and the creation of hyperpolarized long-lived magnetic states are illustrated. It finishes by describing how the recently reported SABRE-RELAY approach offers a route for parahydrogen to hyperpolarize a much wider array of molecular scaffolds, such as amides, alcohols, carboxylic acids and phosphates, than was previously thought possible. We predict that collectively these developments ensure that SABRE will significantly impact on both chemical analysis and the diagnosis of disease in the future.