Do the FDA’s gadolinium findings change everything—or nothing?

Is it safe to dive headfirst into the roiling, gadolinium-spiked waters of MR imaging? At the moment, it would seem so.

On May 22, the FDA issued an eagerly anticipated status report on its nearly two-year investigation into gadolinium-based contrast agents (GBCAs). These are used in around one of every three MRI exams, to the tune of approximately 30 million injected patients per year. The substances can improve diagnostic accuracy on MRI in everything from bones to blood vessels, cancer to heart disease.

The word from FDA was welcome and the news was, in fact, very good. After poring over study after study, animal as well as human, and presumably scrutinizing an awful lot of adverse-event reports, the agency said it could find no connection between the MRI enhancers and health harms of any sort.

That’s none as in zilch. Nada. Zip. It goes for the brain, the anatomic locus of greatest concern, and it goes for linear (“open chain”) as well as macrocyclic (“caged”) GBCAs. This is an important wrinkle since linear chelates allow more of the heavy metal to elude flushing through the kidneys and, instead, plant themselves for a long stay in human tissue.

And now their lasting presence has effectively been proven powerless in all patients except those who are obviously not good contrast candidates due to preexisting kidney failure.

How are FDA’s conclusions going to go over, given the guilty-until-proven-innocent stance some have been taking toward GBCAs since they came under increasing suspicion starting around 2013?

It’s hard to say. The GBCA conversation will probably never return to pre-2013 levels of ho-hum shop talk, although there were signs the gathering circle of concern had begun to dissipate even before May 22. For example, in April the European Medicines Agency said it would rethink its earlier decision to yank linear GBCAs from the market. The American College of Radiology leveraged the moment by reiterating its judicious yet clear support of linear GBCAs. And in May market research showed worldwide demand for gadolinium is growing fast, not least in healthcare.

Of course, it takes a little time to turn momentum in its opposite direction even when it’s been building at a reasonable rate. Item: In May, a patient alleged she’d developed Gadolinium Deposition Disease. She filed a complaint in San Francisco County Superior Court accusing a GBCA maker of negligence, fraud and misrepresentation. According to the Northern California Record, she’s seeking compensatory and punitive damages, along with lost income and more.

Then again, the FDA isn’t calling for a reversal of the careful-use recommendations it made upon announcing the GBCA investigation in 2015. On the contrary, it’s underscoring them while also keeping itself open to any new evidence that may come to light.

“As is appropriate when considering the use of any medical imaging agent,” the agency wrote in its May 22 announcement, “healthcare professionals should limit GBCA use to circumstances in which additional information provided by the contrast agent is necessary” and “assess the necessity of repetitive MRIs with GBCAs.”

To state the gist another way: MR imagers need not hold back from diving into those GBCA waters whenever a case calls for it. They just need to make sure the tide is high enough for the one who’s really taking the leap—the patient.