magnetic resonance imaging (MRI)

The visualisation of the distribution of nuclear spins (usually water) in a body by using a magnetic field gradient (NMR imaging). A similar technique, but less widely used, is to visualise the distribution of paramagnetic centres (EPR imaging).
Source:
PAC, 1997, 69, 1251 (Glossary of terms used in bioinorganic chemistry (IUPAC Recommendations 1997)) on page 1284