Creation of long-lived singlet states of gases and their use as inhalable MRI contrast agents

A method for preserving a long-lived state of hyperpolarized gas, the method comprising:

• (a) mixing parahydrogen gas with an unsaturated precursor in an absence of paramagnetic gases and impurities;
• (b) performing a chemical reaction of the unsaturated precursor with parahydrogen by passing the mixture prepared in step (a) over or through hydrogenation catalyst for molecular addition and without scrambling of parahydrogen hyperpolarization of the parahydrogen to the unsaturated precursor in a low magnetic field, so as to generate a hyperpolarized long-lived singlet state gas;
• (c) maintaining the hyperpolarization of the hyperpolarized long-lived singlet state gas produced in step (b) at the low magnetic field where the H—H spin-spin coupling (J-coupling) of nascent parahydrogen protons in a reaction product is greater than a difference of chemical shifts of these two protons in units of Hertz;
• (d) transporting the long-lived hyperpolarized long-lived singlet state gas to a low-field MRI scanner while maintaining the low magnetic field, and (e) performing a low-field MRI scan while continuing to expose the hyperpolarized long-lived singlet state gas to the low magnetic field, wherein the hyperpolarized long-lived singlet state gas is in a singlet state that has a relaxation time constant of at least 5 seconds.