Recent studies have shown that gadolinium-based contrast agents (GBCAs) used in magnetic resonance imaging (MRI) deposit in the brain of some patients who have repeated scans. The Food and Drug Administration (FDA) is investigating possible health risks of such deposits.
Recent publications in the medical literature—including an article published in March in Radiology—have reported that deposits of GBCAs remain in the brains of some patients who undergo four or more contrast MRI scans, long after the last administration of the agent. The FDA says it is not known whether gadolinium deposits are harmful or can lead to adverse health effects.The FDA is working with the research community and the industry to understand the mechanism of gadolinium retention and to determine if there are potential adverse health effects from retained gadolinium. The FDA’s National Center for Toxicological Research (NCTR) will be involved in the study of this possible safety risk. Based on the information available at this time, the FDA is not requiring manufacturers to make changes to the labels of GBCA products.
Contrast agents are used to increase the visibility of internal body structures in MRI scans. MRI contrast agents may be injected or administered orally. Oral administration is suited to gastrointestinal tract (GI) scans, while intravascular administration proves more useful for most other scans. GBCAs are mostly eliminated from the body through the kidneys, but trace amounts of gadolinium may stay in the body long-term, according to the FDA. Studies conducted in both people and animals have confirmed that gadolinium can remain in the brain, even in individuals with normal kidney function. Researchers advise that GBCAs should not be given to any individual with chronic kidney disease. Currently available information has not identified any adverse health effects, the FDA says.
Because adverse health consequences of gadolinium accumulation may be identified, the FDA recommends that health care professionals reduce the potential for gadolinium accumulation by limiting GBCA use to circumstances in which the additional information provided by the contrast is necessary. Health care professionals are also urged to reassess the necessity of repeat GBCA MRIs. Patients, parents, and caregivers should talk with health care professionals if they have any questions about the use of GBCAs with MRIs. The FDA explains that this issue affects only GBCAs and does not apply to other types of contrast agents used for other imaging procedures, such as radioisotopes or those that are iodine-based.
The FDA encourages health care professionals and patients to report adverse events or side effects related to the use of these products to the FDA’s MedWatch Safety Information and Adverse Event Reporting Program: www.fda.gov/MedWatch/report.