Methods of magnetic resonance imaging (MRI) using contract agent solutions formed from the dissolution of hyperpolarised materials

A method as claimed in any one of the preceding claims wherein said solid MR imaging agent is a water-soluble high T1 agent.

A method as claimed in any one of the preceding claims wherein said MR imaging agent retains its polarisation when transported in a substantially uniform magnetic field and at low temperature.

A method as claimed in any one of the preceding claims wherein the solution formed retains its polarisation in frozen form.

A method as claimed in any one of the preceding claims wherein a magnetic field is present during the dissolution stage.

A method as claimed in any one of the preceding claims wherein step (i) comprises:

• i) irradiating a solid compound having a singlet electronic ground state and containing a non zero nuclear spin nucleus with light to generate an excited polarized triplet electronic state of said agent;
• ii) transforming electronic polarization of said solid compound into a nuclear spin polarization in a soluble solid MR imaging agent to form a nuclear spin polarised MR imaging agent;
• iii) dissolving said polarised MR imaging agent in an aqueous medium.

Use of a paramagnetic substance for the manufacture of an MR imaging composition for use in a method of diagnosis involving generation of an MR image by MR imaging of a human or non-human animal body, wherein manufacture of said composition involves spin refrigeration nuclear spin polarisation of said MR imaging agent.

Use of an MR imaging agent for the manufacture of an MR imaging composition for use in a method of diagnosis involving generation of an MR image by MR imaging of a human or non-human animal body, wherein manufacture of said composition involves spin refrigeration nuclear spin polarisation of said MR imaging agent.

An MR imaging composition comprising a solution of a spin refrigerator nuclear spin polarised MR imaging agent in a physiologically tolerable solvent, optionally together with one or more physiologically tolerable excipients.

A process for the preparation of a nuclear spin polarised MR imaging agent, said process comprising irradiating a solid compound having a singlet electronic ground state and containing a non zero nuclear spin nucleus with light to generate an excited polarized triplet electronic state of said agent;

• transforming electronic polarization of said solid compound into a nuclear spin polarization in a soluble solid MR imaging agent to form a nuclear spin polarised MR imaging agent, optionally dissolving said MR imaging agent in an aqueous medium (preferably a physiologically tolerable medium), and optionally storing said polarised MR imaging agent at a reduced temperature and at a magnetic field of greater than 10 mT.

A process for the preparation of a polarised electronic triplet state of a solid compound having a singlet electronic ground state said process comprising irradiating said compound in a solid state with a first radiation of a wavelength selected to excite said compound from a ground singlet electronic state to an excited singlet electronic state and with a positively or negatively, circularly polarised second radiation of a wavelength selected to excite said compound from the lowest triplet electronic state to the next-to-lowest triplet electronic state.

Use of a water-soluble, heterocyclic chromophore-containing compound containing an I=½ nucleus for the manufacture of an MR imaging composition for use in a method of diagnosis involving generation of an MR image by MR imaging of a human or non-human animal body, said manufacture comprising nuclear spin polarisation of said compound in the solid state and dissolution of the nuclear spin polarised compound in an aqueous medium.