ARIEL, Israel, April 6 (UPI) -- A recent study raises questions about the safety of contrast agents used for MRI scans, with researchers calling for the FDA to investigate their concerns.
Researchers in Israel found gadolinium-based contrast agents, used to help read MRI scans, leave deposits in the brain, bone and other organs despite being used with addition chelator drugs designed to flush the metal out of the body.
Gadolinium has been used as part of the scans for 30 years, and is employed with about 30 million patients per year, or roughly 30 percent of MRI scans.
Concerns have been mounting in the last decade about gadolinium toxicity, with the FDA ordering a black box warning label in 2007 be added outlining the risk for patients with kidney disease to develop nephrogenic systemic fibrosis.
In 2015, a University Hospital Zurich study found gadolinium led to deposits on the brain. The FDA also looked into the risk for brain deposits of patients receiving repeated MRIs with the agents, finding no adverse health effects from it.
"With the ominous discovery that gadolinium is retained in healthy patients, there is a critical shortage of scientific information regarding how to assess gadolinium toxicity, and perhaps most importantly, how to treat it," Moshe Rogosnitzky, a researcher at the Center for Drug Repurposing at Ariel University, said in a press release.
For the new study, published in the journal BioMetals, researchers analyzed studies on gadolinium toxicity and the potential for it to remain in the body.
Researchers report "not one single, suitable drug to swiftly remove gadolinium from the body" was found in the studies they reviewed. In one study, Rogosnitzky said, the researchers suggested it could take 156 years to remove the metal from a patient's body using a particular drug they focused on.
Rogosnitzky said further research is needed not only into other drugs to remove the metal, but on all existing chelator drugs available for other metal toxicities to see if they could be used with gadolinium. The researchers also call on the FDA to more rigorously look into the potential adverse effects of heavy metal buildup in the body.
"Given the ever-growing toxicological and gadolinium tissue retention data, it is vital that the FDA promptly leads efforts, including retrospective and prospective clinical studies, to better define the connection between GBCA-exposure and adverse health events," Dr. Stacy Branch, a toxicologist at the MedInsight Research Institute, said. "This is needed to guide the choice of preventive methods, achieve accurate diagnoses, implement effective treatment approaches, and spark research for the design of safer contrast agents and imaging protocols."