Future directions in magnetic resonance contrast media

In June 1988 Gd DTPA became the first MR contrast agent to be approved for clinical use in adult patients in the United States. Initial approval was given for its use in imaging of the head. One year later approval was extended to include spine studies. This was soon followed by approval for use in children aged 2 years and older. Research is continuing to expand the applications of Gd DTPA in MR imaging of the musculoskeletal system, abdomen, and in MR angiography. Research is ongoing in the development of new agents, attempting to reduce toxicity, permit increased doses, or target specific organs. Gd DOTA has been in clinical use in Europe for approximately 1 year. Two neutral (nonionic) agents, Gd HP-DO3A and Gd DTPA-BMA, have just completed phase III clinical trials. Mn DPDP and AMI-25 are two targeted compounds that have entered clinical trials. Formulations intended for opacification of the gastrointestinal tract, with both Gd DTPA and magnetic particles, have been evaluated in Europe and in the United States.