Patients who received Omniscan contrast dye prior to an MRI may experience greater gadolinium retention compared to those who receive Dotarem, according to a study recently published in the medical journal Radiology.
The authors of the study administered repeated injections of Omniscan (gadodiamide) or Dotarem (gadoterate) to rats over the course of a 5-week period. The animals were then followed for 12 months, with brain and plasma samples analyzed at various points.
“After repeated administration of gadodiamide, a large portion of gadolinium was retained in the brain, with binding of soluble gadolinium to macromolecules,” the authors concluded. “After repeated injection of gadoterate, only traces of the intact chelated gadolinium were observed with time-dependent clearance.
The study authors also noted that the traces of Dotarem they did detect were chelated, indicating that the chemical barrier designed to protect the body from toxic gadolinium remained intact.
Gadolinium is a highly toxic heavy metal that does not occur naturally in the human body. It is used during MRI procedures to improve the images that show up on a scan.
Currently, 8 MRI contrast dyes are approved for use in the United States:
The only known side effect associated with gadolinium-based MRI contrast dyes is a condition called nephrogenic systemic fibrosis, or NSF, which only occurs in people with pre-existing kidney failure.
However, in December 2017, the U.S. Food & Drug Administration (FDA) announced a new class warning regarding the potential for gadolinium deposits to be retained in a patient’s body, including the brain weeks, months, or even years after an MRI.
Among other things, the FDA noted gadolinium contrast dyes known as linear agents result in more retention and retention for a longer time compared to gadolinium products called macrocyclic agents.
Linear agents include:
“Gadolinium levels remaining in the body are higher after administration of Omniscan (gadodiamide) or OptiMARK (gadoversetamide) than after Eovist (gadoxetate disodium), Magnevist (gadopentetate dimeglumine), or MultiHance (gadobenate dimeglumine),” the agency stated. “Gadolinium levels in the body are lowest after administration of Dotarem (gadoterate meglumine), Gadavist (gadobutrol), and ProHance (gadoteridol); the gadolinium levels are also similar across these agents.”
A growing number of lawsuits have been filed in recent months on behalf of patients who are alleged to have suffered permanent symptoms of gadolinium toxicity – Gadolinium Deposition Disease – related to the retention of Omniscan and similar gadolinium-based MRI contrast dyes.
The complaints claim that the manufacturers of gadolinium contrast agents have long been aware of the potential for gadolinium retention in patients with normal kidney function, but failed to update their product labels to reflect the extensive evidence of this risk.