A group representing Canadian radiologists has issued new guidelines for the use of gadolinium-based MRI contrast dyes, amid growing concern that deposits left behind by these agents could lead to serious and potentially permanent health consequences.
The guidelines were established by a Working Group that was asked to:
A Position Statement based on the Working Group’s review was published online by the Canadian Association of Radiologists Journal in September.
Among other things, the Position Statement cautions radiologists to use gadolinium-based MRI contrast dyes only when needed, and after a careful consideration of their risks and benefits. Standard dosing should be used and repeat administrations should be avoided unless necessary.
While emerging research suggests that linear agents are more likely to result in gadolinium retention compared to their macrocylic counterparts, the Working Group concluded that there wasn’t sufficient evidence to recommend one class over another.
“The panel considered it inappropriate to withhold a linear GBCA if a macrocyclic agent is unavailable, if hepatobiliary phase imaging is required, or if there is a history of severe allergic reaction to a macrocyclic GBCA.,” the statement’s authors wrote. “Further study in this area is required, and the evidence should be monitored regularly with policy statements updated accordingly.”
Gadolinium-based dyes are injected just prior to an MRI to improve the visibility of organs, tumors, and blood vessels on imaging scans.
Currently, 8 such agents are approved for use in the United States, including 5 linear dyes:
And 3 macrocylic agents:
Until recently, it was thought that the gadolinium was eliminated from the body fairly quickly in patients without pre-existing kidney impairment. However, in December 2017, the U.S. Food & Drug Administration (FDA) warned that gadolinium deposits could remain the brain and other organs for months – and even years – even among patients with healthy kidneys.
While the agency has not yet linked this phenomenon to any adverse events, it has mandated that information about gadolinium retention be included in the labeling for all gadolinium-based MRI contrast dyes sold in the United States. The manufacturers of these products have also been directed to conduct animal and human studies to help the FDA better assess their safety.
Dozens of gadolinium-based MRI contrast dye lawsuits have been filed in U.S. courts on behalf of individuals who were allegedly harmed by gadolinium retention. Plaintiffs pursing these cases purportedly suffer from Gadolinium Deposition Disease, a disorder characterized by at least one of the following symptoms:
Plaintiffs claim that that the manufacturers of MRI contrast dyes have long been aware of the potential for gadolinium deposits to accumulate in organs and tissues, but marketed the products without adequate safety warnings.
Plaintiffs further allege that they would have avoided debilitating gadolinium side effects if proper warnings had been made available.