Method of magnetic resonance investigation

This invention provides a method of magnetic resonance investigation of a sample, preferably of a human or non-human animal body, said method comprising: (i) producing a hyperpolarised solution of a high T1 agent by dissolving in a physiologically tolerable solvent a hyperpolarised solid sample of said high T1 agent; (ii) where the hyperpolarisation of the solid sample of said high T1 agent in step (i) is effected by means of a polarising agent, optionally separating the whole, substantially the whole, or a portion of said polarising agent from said high T1 agent; (iii) administering said hyperpolarised solution to said sample; (iv) exposing said sample to a second radiation of a frequency selected to excite nuclear spin transitions in selected nuclei e.g. the MR imaging nuclei of the high T1 agent; (v) detecting magnetic resonance signals from said sample; and (vi) optionally, generating an image, dynamic flow data, diffusion data, perfusion data, physiological data (e.g. pH, pO2, pCO2, temperature or ionic concentrations) or metabolic data from said detected signals, wherein said high T1 agent in said hyperpolarised solution has a T1 value (at a field strength in the range 0.01-5T and a temperature in the range 20-40 °C) of at least 5 seconds.