The NMR Center contains two animal MRI instruments: a 2.0-Tesla, 45-cm-bore instrument and a 4.7-Tesla, 40-cm-bore instrument. Upgrades of principal components keep these systems state-of-the-art. The principal investigator performs periodic performance checks, routine component changes, and cryogen ordering and filling as needed, and assists system operators with protocol development and continuing training. Investigators from the cooperating units occasionally assist the principal investigator (Dr. Barnett helps with the 2.0-T instrument, and Dr. McLaughlin helps with the 4.7-T instrument). During this period, a 3.5-cm-bore, ultrafast gradient set was installed for microimaging, in addition to a 15-cm-bore, shielded gradient set. Newly released Omega 6.0.3 software was installed and adapted to our environment. We also anticipate upgrading the console of one of the instruments.