MRI imaging is used to help diagnose many conditions. It can provide images of structures in your body and help show areas of concern. If your doctor thinks you may have multiple sclerosis, an MRI can help them diagnose it.
No single test can definitively diagnose multiple sclerosis (MS). Diagnosis is based on symptoms, clinical evaluation, and a series of diagnostic tests. An MRI scan is one of them.
A type of imaging test called an MRI scan is an important tool in diagnosing MS.
This imaging is able to show areas of inflammation, demyelination, and scarring (also known as plaques) on the brain or spinal cord. Sometimes, these changes are described as lesions. The appearance of demyelination (damage to the myelin that covers certain nerves) is a hallmark of MS.
MRI can also help doctors monitor MS disease activity and progression.
If you have symptoms of MS, your doctor may order an MRI scan of your brain and spinal cord. The MRI images will allow doctors to see MS-associated changes in your central nervous system (CNS).
MS changes may show up as white or dark spots, depending on the type of damage and the type of scan.
MRI is noninvasive and doesn’t involve radiation. It uses a powerful magnetic field and radio waves to transmit information to a computer. This then translates the information into cross-sectional pictures that your doctor can look at.
Contrast dye, a substance that’s injected into your vein, can be used to make some types of lesions show up more clearly on an MRI scan.
Although the procedure is painless, the MRI machine makes a lot of noise, and you must lie very still for the images to be clear. The test takes about 45 minutes to an hour.
It’s important to note that the number of lesions shown on an MRI scan doesn’t always correspond to the severity of your symptoms. Having lesions also does not necessarily mean you have MS.
This is because not all lesions in the CNS are due to MS, and not all people with MS have visible lesions.
MRI with contrast dye can show disease activity by highlighting a pattern that indicates active inflammation. This happens as a result of demyelination.
The contrast images also show areas of permanent damage, which can appear as dark holes in the brain or spinal cord.
Following an MS diagnosis, some doctors will repeat an MRI scan if troubling new symptoms appear or after you begin a new treatment. Analyzing the visible changes in the brain and spinal cord may help construct current treatment and future options.
Your doctor may also recommend additional MRI scans of your brain, spinal cord, or both at certain intervals to monitor disease activity and progression. How often you need to repeat the scan depends on your treatment and the type of MS you have.
Your MRI can help diagnose the impact of MS, but your doctor will make diagnostic and treatment decisions based on a combination of your symptoms, physical exam, and MRI — not on your MRI alone.
Clinically isolated syndrome
A single neurologic episode caused by inflammatory demyelination and lasting at least 24 hours is called clinically isolated syndrome (CIS). You may be considered at high risk of MS if you’ve had CIS and an MRI scan shows MS-like lesions. This is because MS often starts with CIS.
If you have CIS and your MRI shows lesions, your doctor may consider starting you on a disease-modifying MS treatment to help delay or prevent a second attack.
However, the treatments can have side effects. Your doctor will weigh the risks and benefits of treatment with your chance of developing MS before recommending disease-modifying treatment.
Someone who has had symptoms but no MRI-detected lesions is considered at a lower risk of developing MS than someone who has lesions.
Relapsing-remitting MS
People with all forms of MS can have lesions, but people with a common type of MS called relapsing-remitting MS generally have recurrent episodes of inflammatory demyelination. During these episodes, active areas of inflammatory demyelination are sometimes visible on an MRI scan when contrast dye is used.
In relapsing-remitting MS, distinct inflammatory attacks cause localized damage and accompanying symptoms. Each distinct attack is called a relapse. Each relapse eventually subsides (remits) with periods of partial or complete recovery that are called remissions.
Primary progressive MS
Rather than intense bouts of inflammatory demyelination, progressive forms of MS involve a steady progression of damage. The demyelinating lesions seen on an MRI scan may be less indicative of inflammation than those of relapsing-remitting MS.
With primary progressive MS, the disease is progressive from the start and doesn’t involve frequent distinct inflammatory attacks.
Secondary progressive MS
Secondary progressive MS is a stage that some people with relapsing-remitting MS will progress into. This form of MS is classified into stages of disease activity and remission, along with new MRI activity.
Additionally, secondary progressive forms include stages during which the condition worsens on a more gradual basis, similar to primary progressive MS.
If you have what you think may be MS symptoms, talk with your doctor. They may suggest an MRI scan to help diagnose your condition.
An MRI can help visualize inflammation and patterns of damage to the brain or spinal cord. This can help determine the type of MS you may have.
Your doctor will explain the procedure to you in detail, but if you have questions, make sure to ask them before you have the scan.
