Often there is an uncomfortable gap between questioning whether a drug or medical device is safe and having proof that it is unsafe. The radiology community has been navigating in that space with gadolinium-based contrast agents. The new version of the ACR’s Manual on Contrast Media recognizes and addresses that issue: “While various factors may have influenced the number of cases reported with each of these agents, investigators believe that intrinsic properties of these three agents increase the relative likelihood of NSF developing following exposure in at-risk patient.”

While MR contrast experts aren’t don’t have sufficient data to report exactly what factors make using Magnevist, Omniscan, or Optimark too risky in patients at high risk for developing nephrogenic systemic fibrosis (NSF), the ACR clearly believes that risk is real—and greater in some gadolinium-based agents than others. The new ACR manual reflects that position and gives patients the benefit of the doubt. The new Manual on Contrast Media categorizes the three MR contrast agents as Group I agents and recommend that they not be used in patients at high risk for NSF. Here is the complete list from the new manual:

Group I: Agents associated with the greatest number of NSF cases:
Gadodiamide (Omniscan® – GE Healthcare)
Gadopentetate dimeglumine (Magnevist® – Bayer HealthCare Pharmaceuticals)
Gadoversetamide (OptiMARK® – Covidien)

Group II: Agents associated with few, if any, unconfounded cases of NSF:

Gadobenate dimeglumine (MultiHance® – Bracco Diagnostics)
Gadoteridol (ProHance® – Bracco Diagnostics)
Gadoteric acid (Dotarem® – Guerbet)*
Gadobutrol (Gadovist® – Bayer HealthCare Pharmaceuticals)*

*Not FDA-approved for use in the United States.

Group III: Agents which have only recently appeared on the market in the US:
Gadofosveset (Ablavar® – Lantheus Medical Imaging)
Gadoxetic acid (Eovist® – Bayer HealthCare Pharmaceuticals)
Experts clearly came down on the side that not all gadolinium-based contrasts pose the same NSF risks. Fortunately, precautions against using gadolinium contrast in patients with low glomular filtration rates have practically eliminated new NSF cases since late 2007.