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Study Questions Safety of MRI Contrast Agent
An article published in the journal BioMetals has raised questions about the safety of the gadolinium-based contrast agents that are used in approximately 30% of magnetic resonance imaging (MRI) scans. Researchers in Israel analyzed studies detailing the known and proposed mechanisms of retained gadolinium toxicity. Although gadolinium is bound to chelating agents designed to flush the rare metal out of the body after an MRI, deposits have been found in the brain, bone, and other organs, according to lead author Dr. Moshe Rogosnitzky.
Rogosnitzky said that this finding contradicts the longstanding belief that patients with normal kidney function are not at risk for gadolinium accretion. In 2007, the FDA added a boxed warning to the labels for gadolinium-based contrast agents after it was discovered that patients with kidney disease were developing nephrogenic systemic fibrosis (NSF) as a result of the inability to clear gadolinium from their bodies. In July 2015, the FDA announced it was evaluating the risk of brain deposits in patients who undergo repeated exposure to gadolinium-based contrast agents.
“At the time, the FDA claimed that available information did not identify any adverse health effects. In the face of the information contained in our study, we believe this position is no longer tenable,” Rogosnitzky said.
Co-author Dr. Stacy Branch added: “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. 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.”
Rogosnitzky called on the scientific community to develop treatments for gadolinium overload. “Our literature review did not reveal a single suitable drug to swiftly remove gadolinium from the body,” he said. “In one study, the authors estimated it might take up to 156 years to remove a patient’s stored gadolinium using a particular drug.”
Rogosnitzky believes that a good first step is to study existing chelator drugs used for other metal toxicities in order to assess their possible utility in patients with gadolinium accumulation.
Sources: Medical Xpress; April 6, 2016; and BioMetals; April 6, 2016.