Study: MRI contrast agents leave heavy metal deposits in brain

"Linear"-type gadolinium-based contrast agents are given about 30 million times a year.
By Stephen Feller   |   June 25, 2015 at 3:49 PM
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WASHINGTON, June 25 (UPI) -- Repeated use of specific "linear"-type gadolinium-based contrast agents, or GBCAs, for MRIs leads to deposits of the heavy metal gadolinium in the brain, according to a new study.

The agents have been widely used in MRIs since their approval in 1988, with roughly 30 million doses given each year.

"This important safety issue may lead to certain linear GBCAs not being used in the future," said Val M. Runge, M.D., of University Hospital Zurich, in a press release. Runge, editor-in-chief of the journal Investigative Radiology, which published the study, first proposed the concept of using gadolinium as a contrast agent in 1982 and demonstrated the effectiveness of the first GBCA developed in 1984. "All of the currently approved GBCAs should be evaluated by the methods used" in this study, he added.

Based on recent studies that have called into question the safety of GBCAs, researchers compared the MRI results of three groups of rats. One group was given high doses of traditional linear GBCAs, the second group was given a different GBCA, the "macrocyclic" agent called gadoterate meglumine, and the third group received saline.

The study, funded by Guerbet, the manufacturer of gadoterate meglumine, found that rats given linear GBCAs showed abnormalities in their cerebellums on MRIs that researchers determined to be deposits of gadolinium.

While some linear GBCAs have been linked to a rare disease, nephrogenic systemic fibrosis, in patients with impaired kidneys, they have been widely used for about 30 years without major safety concerns being raised. Runge said, however, that the lack of issues thus far shouldn't be a concern.

"It is also a toxic heavy metal that is not a normal trace element in the body," Runge said.

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