It’s natural to be worried if you have symptoms that suggest multiple sclerosis (MS), a disease affecting the central nervous system (the brain and spinal cord). If you’re concerned about your symptoms and want an MRI scan to get answers or to rule out MS, we have all the information you need, from how doctors diagnose MS to how it shows up on MRI scans.

What is multiple sclerosis?

Multiple sclerosis is a chronic (lifelong) autoimmune disorder affecting the brain and spinal cord. It’s caused by the immune system attacking the myelin sheath, a protective covering of nerves in the central nervous system.

The destruction of the myelin causes inflammation and damage to the central nervous system, resulting in disrupted signals along the nerve fibres or damage to the fibres themselves. This can cause a wide range of neurological symptoms, ranging from mild to severe. Symptoms also often depend on which part of the central nervous system has been affected. That’s why symptoms of MS can vary from person to person.

MS is most commonly diagnosed in younger people in their 20s, 30s and 40s, although it can happen at any age. It’s more common in women than men and is one of the most common causes of disability in young adults. Around 150,000 people in the UK have MS, and it can affect people from many ethnic backgrounds. There is currently no cure for MS, but doctors can treat and manage symptoms by using MRI scans to pinpoint old and new damage and see how active the condition is.

What are common symptoms of MS?

The main symptoms of MS include:

fatigue and weakness
balance issues
pins and needles, burning or numbness in the skin
sensory loss, such as problems with smell and hearing
vision problems, such as double vision, painful eye movements or loss of vision
pain in the back and sometimes into the limbs
problems with memory and thinking
difficulty walking
muscle stiffness and spasms (spasticity)
bladder and bowel problems
sexual problems

Less common symptoms include:

speech disorders
involuntary facial movements
sleep disturbances
vertigo
swallowing difficulties

How is multiple sclerosis (MS) diagnosed?

The wide variety of symptoms and the fact that they can be different for each person with MS means that diagnosis can be complicated. There are no definitive tests for MS either. That’s why doctors will usually only confirm MS after you have had two attacks of MS-like symptoms before referring you to a neurologist, who will ask you about your symptoms, give you a physical examination and book you in for tests, which may include an MRI scan.

A multiple sclerosis MRI (Magnetic Resonance Imaging) scan takes detailed three-dimensional brain and spinal cord images using powerful magnetic fields and radio waves. The magnets align water molecules in your body first; then, the radio waves knock them out of position. When the molecules realign, they give off signals based on their location. A computer translates those signals into a detailed picture. Unlike X-rays, an MRI uses no radiation. The magnetic fields and radio waves create the images slice-by-slice without pain, contrast dye, surgery or special equipment. Soft tissues like the brain show up exceptionally clearly.

MRI scans play a crucial role in the diagnosis, monitoring and treatment of MS, confirming MS in over 9 in 10 people with the condition. MRI scans can pinpoint damage to the brain and spinal cord caused by MS, such as inflammation and scarring (lesions). A neurologist won’t confirm MS until the results of an MRI scan confirm the condition.

An MS MRI scan takes between 15 and 90 minutes, during which you’ll lie flat on a bed that’s slowly moved into the scanner. It’s painless, but it can be noisy, and some people find the tunnel claustrophobic. You’ll have to lie very still during the scan.

Does MS show up on MRI?

Yes, doctors can identify MS using an MRI scan. MRI images can spot MS-related abnormalities, including lesions, damage and inflammation in the central nervous system. MRI scans can also track the condition’s activity and progression.

When looking for multiple sclerosis, doctors will look at two main types of images:

T2-weighted or FLAIR scans: these show the total damage caused by MS
T1-weighted scans with gadolinium contrast: these show older damage and new, active damage by using a special dye

What does MS look like on MRI images?

How MS shows up depends on the type of MRI scan you have:

A T2-weighted or FLAIR scan shows MS as bright, white spots (lesions) on a black background. It shows areas where the myelin has been damaged and helps doctors determine whether MS is affecting the brain or spinal cord.

A T1-weighted scan with gadolinium contrast shows older damage as darker spots and new and active damage as bright white spots. This allows doctors to see how active the disease is, which helps them plan your treatment more effectively.

Multiple sclerosis MRI vs normal

In a person without MS, the MRI scan would show the brain or spinal cord as generally uniform in colour, with no bright spots or darker areas indicating damage, inflammation or activity.

Early MS MRI

If you’ve just started having symptoms, you may be wondering, does early MS show up on MRI? Yes, early multiple sclerosis can show up on an MRI.

On T2-weighted and FLAIR scans, early MS appears as small bright spots in the brain and spinal cord, indicating early damage to the protective covering of nerve fibres.

On T1-weighted scans with gadolinium contrast, bright spots may appear after a special dye is injected, showing areas of active inflammation and ongoing damage.

Spotting these changes early on an MRI helps doctors diagnose early-stage multiple sclerosis sooner. This is crucial because it allows for earlier treatment, which can slow the disease's progress.

Does MS always show up on MRI? Can MS be missed on MRI?

It’s possible for an MRI scan to miss MS in the very early stages of the disease. This might be because the lesions are too small or too few to be picked up by the MRI or because they are in an area that is hard to image. It’s also possible that the quality of the scanning machine will affect the results. It’s also possible for MS to be missed if the magnetic fields are not strong enough, the technician doesn’t use the correct imaging techniques, or the radiologist cannot definitively interpret the images as showing signs of MS.

Can a CT scan detect MS?

CT scans are not typically used to diagnose MS. Although a CT scan can detect abnormalities in the brain, it’s not sensitive enough to detect the damage caused by MS. It doesn't show the small, detailed lesions that an MRI can. MRI is much better at seeing the brain and spinal cord soft tissues, which is essential for spotting MS.

Which MS scan to choose?

MRIs provide the most detailed and accurate imaging of MS. Don’t worry if you’re still not sure whether a private MRI scan is best for you, or what the difference is between an MRI and CT scan of the brain. All Scan.com bookings include two clinical consultations. One happens before the scan to ensure your clinician recommends the best scan for you in light of your symptoms. The second consultation takes place after the scan, where your clinician will clearly explain the results and the next steps. Even after you’ve had the first consultation, there is no obligation to go ahead and book an MRI scan. The decision is up to you.

Sources

Feng, Y, et al. (2019). A self-adaptive network for multiple sclerosis lesion segmentation from multi-contrast mri with various imaging sequences. https://ieeexplore.ieee.org/document/8759522/

How is MS diagnosed? (N.D.) https://www.mssociety.org.uk/about-ms/diagnosis/the-tests-for-ms

MRI and MS: 7 things you need to know. (2017). https://www.mssociety.org.uk/research/latest-research/research-blog/mri-and-ms-7-things-you-need-know

Multiple sclerosis. (2022). https://www.nhs.uk/conditions/multiple-sclerosis/

Multiple Sclerosis. (2023).https://www.ninds.nih.gov/

Multiple sclerosis in adults: management. (2022). https://www.nice.org.uk/guidance/ng220/chapter/Recommendations#diagnosing-multiple-sclerosis

What is MS? (2021). https://www.mssociety.org.uk/sites/default/files/2021-04/What%20is%20MS%20Mar%202021%20%28web%29_0.pdf