What Are the Risks Associated with Contrast Dyes for MRIs?

If you have MS, you should know about possible risks associated with MRIs.

What Is an MRI?

Magnetic resonance imaging (MRI) is the gold standard for diagnosing and monitoring the progress of multiple sclerosis. MRI imaging uses magnetism and radio waves to create pictures of internal organs; in many cases an MRI can provide valuable information without any sort of invasive procedure. Unlike X-rays, which can image only hard structures such as bones, MRI's can create images of soft structures and tissues.

The MRI itself is a benign procedure, assuming that you have no metal in your body. Pacemakers, artificial bones or joints, and even IUD's can cause problems as the MRI uses very strong magnets to create images. MRI machines are also problematic for people with claustrophobia -- though more imaging centers are using open MRI's that produce less anxiety.

How MRI's Are Used to Diagnose and Monitor MS

MRI's of the brain and cervical spine are used to diagnose MS. The purpose of the MRI is to identify plaques, or lesions, on nerve fibers. These plaques don't always indicate MS, but in the presence of symptoms they can help with a diagnosis. In some cases, plaques do not cause symptoms, but in other cases the progression of the disease can injure or even destroy nerve fibers. Once MS has been diagnosed, many physicians suggest an annual MRI to monitor the progress of the disease.

MRI scans can be done with or without a contrast dye.

The dye, based on a chemical called Gadolinium, can actually "light up" plaques on nerve fibers, making it much easier to identify and quantify lesions. The dye is infused at the time of the procedure.

Safety Concerns About Gadolinium-Based Contrast Dyes

The dye used to enhance MRI scans can have side effects, usually in people with compromised renal function (kidney failure).

In 2015, after studies were conducted, the FDA issued a Safety Communication about contrast agents:

The U.S. Food and Drug Administration (FDA) has issued a Safety Communication about gadolinium-based contrast agents (GBCAs) which are frequently used to identify new disease activity in MRI scans, including those of people with MS. Research suggests that small amounts of GBCAs may be deposited in certain areas of the brain in some people who have received multiple doses of GBCAs. These deposits were identified years after the administration of the contrast agent, indicating that the contrast agent was not completely eliminated from the body.

The safety communication makes the statement: "It is unknown whether these gadolinium deposits are harmful or can lead to adverse health effects." 

Gadolinium can also cause brief but unpleasant side effects such as headache, nausea, and dizziness. People who are allergic may experience hives or other reactions.

Because gadolinium is the best known tool for observing the progress of MS, it is still used in most instances. If you have concerns, the best approach is to discuss options with your doctor; it is possible to have a non-dye MRI, but the outcome may not be as helpful in visualizing MS plaques.

For more information, read the articles:


National Muscular Sclerosis Society. FDA to Study Potential Risks Related to a Commonly Used MRI Contrast Agent. Website. 2016. http://www.nationalmssociety.org/About-the-Society/News/FDA-to-Study-Potential-Risks-Related-to-a-Commonly

Ramalho J., et al. Gadolinium-based contrast agent accumulation and toxicity: an update. American Journal of Neuroradiology. Published December 10, 2015 as 10.3174/ajnr.A4615

US Food and Drug Administration. FDA Drug Safety Communication: FDA evaluating the risk of brain deposits with repeated use of gadolinium-based contrast agents for magnetic resonance imaging (MRI).Website. 2016. http://www.fda.gov/Drugs/DrugSafety/ucm455386.htm

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