MRI Contrast Side Effects in Multiple Sclerosis

Magnetic resonance imaging (MRI) is the gold standard test for diagnosing and monitoring the progression of multiple sclerosis (MS).

Some types of MRI require using gadolinium-based contrast dye (GBCD).

The dye frequently causes side effects, such as nausea, headaches, dizziness, and rash, but they tend to be mild.

GBCD is administered through a vein during the MRI, causing active MS lesions to "light up."

After an MRI, most GBCD is removed from the body in urine, but trace amounts may stay in the body and accumulate over time in people who have MRI scans with GBCD frequently.

This article discusses how GBCD works, its use, and the possible side effects and complications it may cause in some people.

How GBCDs Work

Gadolinium is a chemical compound. When injected into the bloodstream, it usually can't get past the blood-brain barrier—a layer of membranes and cell processes that prevents substances in the blood from entering the brain or spinal cord.

The blood-brain barrier is largely impenetrable. 

However, under certain circumstances, such as active inflammation within the brain or spinal cord that occurs during an MS relapse, the barrier is disrupted.

When this happens, gadolinium can enter the brain or spinal cord and leak into an MS lesion, causing it to appear as a highlighted spot on an MRI. 

Side Effects of Gadolinium-Based Contrast Dyes

Most of the side effects of gadolinium-based contrasts (GBCDs) are mild, including:

• Headache
• Nausea
• Dizziness
• A cold sensation when injected

In most cases, side effects occur within one hour after the contrast dye is administered, although there have been reports of side effects occurring one week after administration.

Of more concern is the possibility that the contrast material won't be completely eliminated from the body.

The FDA published this warning even though it wasn't clear if the retention of GBCDs would be harmful over time.

Further research suggests that any gadolinium build-up is dose-dependent—that is, the more times a person receives the dye, the more brain deposits they're likely to have.

The same study concluded that there is no link between the brain deposition of gadolinium-based contrast agents and a person's kidney function, age, gender, or the period between their contrast exposure (their last MRI) and death.

It's also important to note that contrast material is even more likely to be deposited in bone than in brain tissue, although the implications of this aren't yet clear.

Complications and Concerns

Rarely, certain types of gadolinium contrast cause a severe disease called nephrogenic systemic fibrosis in people with significant kidney dysfunction.

This condition, which causes tightening of the skin and damage to internal organs, is most likely to occur in people with MS who also have kidney dysfunction.

Although rare, some people have an allergic reaction to gadolinium contrast. The main symptom is itchy skin, but rashes have also been reported.

A life-threatening allergic reaction, known as anaphylaxis, is also possible but unlikely.

MRI imaging uses magnets and radio waves.

Therefore, pacemakers, artificial bones or joints, and even IUDs can cause problems, as the MRI uses strong magnets to create images.

In addition, MRI machines may be problematic for people with claustrophobia. To minimize this risk, imaging centers increasingly use open MRI equipment.

If you are undergoing an MRI tell your healthcare provider and the MRI technologist if you have any metal implants, claustrophobia, allergies, or kidney problems.

They can tell you what is and is not safe and how to proceed best.

When to See a Healthcare Provider

Serious allergic reactions to contrast dyes are very rare but can happen.

Call 911 or go to the nearest emergency room if you have any of the following signs of a serious allergic reaction:

• Trouble breathing
• Throat tightness
• Shortness of breath
• Wheezing
• Chest pain
• Facial swelling
• Fast heart rate
  

Summary

Gadolinium-based contrast dye (GBCD) is sometimes administered to people having MRI scans to check for signs of multiple sclerosis.

GBCD is linked to several side effects, including nausea, headaches, dizziness, and rash.

Although these side effects are common, they tend to be mild. Most GBCD is eliminated from the body, but trace amounts can stay behind.

Drinking lots of water after your MRI scan can help your body eliminate the contrast dye.

Rarely, severe allergic reactions to contrast dyes can occur. If you develop signs of a severe allergic reaction, call 911 or go to the nearest emergency room immediately.