Retention From Linear Gadolinium Contrast Dye Detected In Rat Brains For A Year

The findings of a new study appear to back up both growing evidence that gadolinium MRI dyes may be retained in the body, and that one particular class of the contrast agents are more prone to result in such retention. 

German researchers from Bayer published a report this week in the medical journal Radiology, which indicates that deposits of gadolinium may linger in rat brains for at least a year. The findings link long-term retention to linear gadolinium-based contrast dyes, which have been strongly linked to gadolinium retention in previous studies.

Gadolinium-based contrast agents are used during MRI and MRA exams to help enhance the images. However, in recent years concerns have emerged about the risk of gadolinium deposition, with studies finding that some users are left with remnants of the toxic metal in their brain, or other parts of the body, long after receiving the contrast dye.

In this latest study, researchers with Bayer injected rats with either linear gadolinium contrast agents, macrocyclic gadolinium MRI dyes, or saline. The linear contrast agents used included Bayer’s own Magnevist, as well as Omniscan and MultiHance. The macrocyclic gadolinium contrast agents included Bayer’s Gadavist, Dotarem and ProHance.

The rats received eight injections over two weeks, researchers then looked for MRI signal intensity changes indicating the presence of gadolinium.

According to the findings, researchers found evidence of concentrations of gadolinium in the cerebellum of rats given linear gadolinium contrast agents a year after the injections. They found no signs of increased gadolinium levels in the brains of rats injected with macrocyclic gadolinium contrast agents.

“Increased signal intensity in the deep cerebellar nuclei of rats persists for at least 1 year after administration of linear gadolinium-based contrast agents (GBCAs), in line with persistent brain gadolinium concentrations with no elimination after the initial 5-week period,” the researchers concluded. “The animals that received macrocyclic GBCAs showed an ongoing elimination of gadolinium from the brain during the entire observation period.”

About a decade ago, the first problems with gadolinium contrast agents emerged among individuals with impaired kidney function, who face an increased risk of developing a severe reaction known as nephrogenic systemic fibrosis (NSF), which causes a progressive thickening and hardening of the skin that severely restricts movement and ultimately results in confinement to a wheelchair or death.

More recently, concerns have emerged about MRI contrast dye reactions among individuals with normal kidneys, as studies have found that the gadolinium may buildup in the body and result in a number of symptoms, such as persistent headaches, cognitive issues, joint pain and other side effects.

The findings come as manufacturers face a growing number of MRI contrast dye lawsuits have been filed on behalf of individuals suffering painful and debilitating reactions after gadolinium deposition allegedly caused fibrosis of organs, bones and skin.