What are Gadolinium Enhancing Lesions in Multiple Sclerosis?

Contrast Will Highlight Areas of Active Inflammaton

Nurse explaining MRI results
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The purpose of a gadolinium-enhanced magnetic resonance imaging (MRI) scan is to give your doctor an indication of the age of your MS lesions, like whether a MS relapse is occurring now or whether one occurred awhile ago (like more than 2 to 3 months).

What is Gadolinium and Why is it Called "Contrast"?

Gadolinium, also called "contrast," is a large, chemical compound that is injected into a person's vein during a MRI scan by a technician.

Gadolinium normally cannot pass from the bloodstream into the brain or spinal cord due to a layer of protection in a person's body called the blood-brain barrier. But during active inflammation within the brain or spinal cord—as during a MS relapse—the blood-brain barrier is disrupted, allowing gadolinium to pass through.

Gadolinium can then enter the brain or spinal cord and leak into a MS lesion, lighting it up and creating a highlighted spot on an MRI. 

What is an MS Lesion that "Lights Up"?

If a lesion on the MRI lights up, it means that active inflammation is occurring, usually within the last two to three months. Active inflammation means that myelin (the fatty sheath that insulates nerve fibers) is being damaged and/or destroyed by a person's immune cells.

If a lesion on a MRI does not light up after gadolinium is injected, then it's likely an older lesion—one that occurred more than 2 to 3 months ago.

In other words, the use of contrast helps a neurologist determine the age of a lesion. 

When is Contrast Ordered?

Your neurologist will likely only order contrast to be given with your MRI if he suspects that your disease is active—meaning you are having a relapse (new or worsening neurological symptoms) or recently had a relapse.

If you are going in for your periodic MRI to determine how your disease is progressing, then contrast is not usually given.

What Does This Mean for Me if I or a Loved One Has MS?

It's important to understand that a MS lesion seen on a MRI does not necessarily cause symptoms. These are referred to as "silent" lesions. Also, not all lesions represent MS, which is why a MRI cannot be used alone to diagnose or monitor a person's MS. Lesions seen on a MRI can be the result of aging or other health conditions like stroke, trauma, infection, or migraine. Sometimes, people have one or more lesions on their MRIs, and doctors cannot explain why.

In addition, lesions do interesting things. Sometimes they get inflamed over and over again and eventually form black holes, which represents areas of permanent or severe myelin and axon damage. Research suggests that black holes correlate with a person's MS-related disability. Sometimes lesions heal and repair themselves (and even disappear).

A Word From Verywell

While it's good to understand your brain and spinal cord MRIs, try not to get too hung up on the number or location of your lesions or spots. It's better to focus on improving your symptoms, feeling good, and keeping yourself as happy and healthy as possible.

 

Sources:

Birnbaum, M.D. George. (2013). Multiple Sclerosis: Clinician’s Guide to Diagnosis and Treatment, 2nd Edition. New York, New York. Oxford University Press.

Giorgio A et al. Relevance of hypointense brain MRI lesions for long-term worsening of clinical disability in relapsing multiple sclerosis. Mult Scler 2014 Feb;20(2):214-9

National MS Society. Magnetic Resonance Imaging.

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