What Can MRI Tell Us about MS Relapses?

MRI, or magnetic resonance imaging, is a non-invasive procedure that uses magnetic fields and radio waves to take detailed pictures (or “scans”) of organs and structures in the body, including the brain and spinal cord. Healthcare providers can use these scans to first diagnose MS and then monitor disease activity and progression over time.

Healthcare providers commonly use two types of MRI scans: the T1-weighted and the T2-weighted scans. Images from a T1-weighted scan can be enhanced by injection of a magnetic contrast agent (gadolinium, or “Gd”) into a patient’s bloodstream, just before the MRI scan is taken.

Gd-enhanced T1-weighted scans show areas in the central nervous system (CNS) where the blood-brain barrier has broken down, signifying inflammation. The blood-brain barrier is a layer of cells around the brain and spinal cord that keeps certain substances in the bloodstream from entering the CNS. Inflamed areas are “active lesions,” that is, they are new or growing larger. In this way, T1-weighted images inform the healthcare provider about current disease activity.

Additionally, T1-weighted scans may also show what appear to be “black holes” in the scans, which are thought to indicate areas of permanent damage.

T2-weighted scans are useful for providing information about disease burden by showing the total amount of lesion area.

When a relapse, also called “flare-up” or “attack,” is suspected, your healthcare provider will ask you about your symptoms. Your responses should be enough to determine whether or not your symptoms are considered a true relapse. But your healthcare provider may decide to give you an MRI to see how MS is affecting your CNS.

Your healthcare provider may consider disease activity on MRI as well as your clinical symptoms and relapses in order to determine whether your current treatment plan is working or if a change in treatment is warranted.

The image shown here is an example of an MRI scan of the brain. Depending on the type of scan taken of a person with MS, lesions and areas of inflammation can appear as either bright white spots or darkened areas.

There is some disagreement about how often MRIs should be done. But many MS clinicians now recommend MRIs on a yearly basis.

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