Gadolinium Found In Dogs’ Brains After Single MRI Contrast Injection: Study

New research appears to add to the growing body of evidence that gadolinium from MRI contrast injections is retained in the body long after the exam.

In a study published in the September issue of the American Journal of Veterinary Research, researchers from Mississippi State University examined what parts of the brain retain gadolinium and what factors could affect the quantity of the toxic metal that remains in the body.

The research was conducted on 14 dogs who were put to sleep after the experiment. Researchers injected 13 dogs with Omniscan (gadodiamide), a linear gadolinium-based contrast agent (GBCA) by GE Healthcare. One dog was injected with a placebo. The dogs were injected three to seven days before their brains were examined.

According to the findings, gadolinium retention was seen in all regions of the brain at all dose levels. The only dog whose brain did not have any gadolinium was the one who received a placebo.

“Gadodiamide exposure resulted in gadolinium retention in the brain of healthy dogs,” the researchers concluded. “Physiologic mechanisms for gadolinium retention remained unclear. The importance of gadolinium retention requires further investigation.”

MRI contrast agents containing gadolinium are typically used to enhance the results of MRI exams, and manufacturers indicate that they are safely processed out of the body before the protective coating surrounding the toxic metal breaks down.

Concerns about the safety of gadolinium contrast agents first emerged about a decade ago, when they were linked to the development of  nephrogenic systemic fibrosis (NSF), a rare and life-threatening condition which was found to occur among patients with impaired kidney function, who are unable to process the gadolinium out of their body. The disease causes a thickening and hardening of the skin that severely restricts movement and ultimately results in confinement to a wheelchair or death.

In 2007, the FDA limited gadolinium contrast doses in most kidney patients and contraindicated it for others, which limited the risk of NSF. In September 2010, the FDA went even further and banned the use of Bayer’s Magnevist on patients with kidney problems, due to the heightened risk of NSF.

The agency also required label changes for all gadolinium agents, warning healthcare professionals to screen patients before injecting gadolinium to identify those suffering from acute kidney injury or chronic, severe kidney disease.

In recent years, new concerns have emerged about the retention of gadolinium in the body of individuals with normal kidney functions, which has been linked to reports of severe and debilitating bone and joint pain, cognitive problems, headaches, skin changes and other complications.

These new complaints are increasingly referred to as gadolinium deposition lawsuits, as individuals often have evidence that the toxic metal is still in their body or brain long after the exam.

In September 2017, the FDA’s Medical Imaging Drugs Advisory Committee voted to recommend the FDA require new MRI contrast agent warnings about the risk of gadolinium build up in the brain. However, in May the FDA concluded that gadolinium in the brain appeared to carry no threat of health effects.

In December 2017, the FDA issued a drug safety communication for gadolinium-based contrast agents, including Omniscan, OptiMark, Magnevist, Gadavist and others, providing new information about the risk of gadolinium retention and potential side effects.

The FDA recommended that health care professionals consider the fact that the body retains gadolinium when deciding whether to give it to patients that may be at higher risk of health problems. These include women who are pregnant or think they may be pregnant, patients with kidney problems, children, and patients when inflammatory conditions. The recommendations also suggest that repeated use of the contrast agents be minimized where possible, particularly when MRIs are scheduled closely together.

Manufacturers now face an increasing number of MRI contrast injection lawsuits brought on behalf of individuals who claim that inadequate warnings were provided about the risk of gadolinium retention among individuals without kidney impairments.