Radiology tests for multiple sclerosis
These changes disrupt the communications between the brain and the rest of the body, leading to a range of symptoms.
The symptoms vary between individuals but can include pain and tingling in the limbs, vision problems, bowel and bladder function disorders, difficulty walking, fatigue, and weakness or numbness in the body.
There is currently no cure for multiple sclerosis (MS), but medication may improve the long-term outlook in some cases. Current guidelines recommend starting treatment as early as possible for maximum effectiveness.
To do this, however, it is crucial to have an accurate diagnosis. No single test can diagnose MS definitively, but imaging tests and spinal fluid analysis can help doctors identify the condition.
Doctors often use an MRI scan to examine the brain and spinal cord and identify any damage that may indicate MS. They also use imaging tests to track the progression of the disease over time.
Radiology in MS diagnosis
An MRI scan is a helpful tool in diagnosing MS.
Doctors do not know exactly why MS happens, but it appears to occur when the immune system mistakenly attacks the myelin sheath that protects the nerve cells.
The resulting lesions, or areas of scarring, are visible on MRI scans of the brain and spinal cord.
MS can be difficult to diagnose because it shares symptoms with other conditions and does not affect everyone in the same way.
It is important that a person gets a correct diagnosis as soon as possible so that they can start appropriate treatment.
Doctors use specific guidelines called the McDonald criteria to decide whether a person has MS.
Before confirming a diagnosis of MS, a doctor must identify indicators of lesions or damage in at least two areas of the brain, spinal cord, or optic nerves.
There must also be evidence that the damage to each of these lesions took place at a different time. A lesion that has existed for some time will usually look different than a recently formed one.
In addition, a person must have experienced an attack of symptoms that lasted 24 hours or more without recovery and did not occur alongside signs of fever or infection.
For more information about MS, read our dedicated article here.
Ruling out other conditions
Further tests can help rule out other conditions that may have similar symptoms, such as:
In one particular type of MS, known as clinically isolated syndrome (CIS), a person can experience one episode of MS-like damage but then never notice any further symptoms.
What to expect
Before having an MRI, a person will need to sign a consent form to say they agree to the test, and the radiologist will ask a number of questions.
The person may need to wear a gown, and they will have to remove any metallic jewelry, hearing aids, or metal items they may be wearing, because the procedure involves a strong magnet.
A person who wears a pacemaker or who has any type of metal in their body should know the details of these devices, to be able to explain to the healthcare professional. Some devices are acceptable during an MRI, but others are not.
An MRI scan is painless, but generating the magnetic field can be very loud. The noises sound like tapping and thumping. Earplugs can help make the noise more manageable.
People with claustrophobia may feel uncomfortable or anxious inside the tube-like MRI machine. Some MRI machines are open and do not have a tunnel, but these do not always produce such high-quality images.
Therefore, most doctors recommend the tunnel-like MRI for MS detection. They will sometimes give a person medication before the test to help reduce anxiety.
The MRI test can last from 15 minutes to an hour or more.
After the test, a person can usually return to their everyday activities. If they received sedation medications, they might need help from another person to get home.
How does MRI for MS work?
An MRI scan is an imaging test that uses a magnetic field and radio waves to create an image by measuring the water content in tissues. It does not involve radiation exposure.
It is an effective imaging method that doctors can use for diagnosing MS and monitoring its progression.
An MRI is useful because myelin, the substance that MS destroys, consists of fatty tissue.
Fat is like oil in that it repels water. As an MRI measures water content, areas of damaged myelin will show up more clearly. On an imaging scan, damaged areas may appear either white or darker, depending on the type of MRI scanner or sequence.
Examples of MRI sequence types that doctors use to diagnose MS include:
T1-weighted: The radiologist will inject a person with a material called gadolinium. Usually, gadolinium's particles are too large to pass through certain parts of the brain. However, if a person has damage in the brain, the particles will highlight the damaged area. A T1-weighted scan will cause lesions to appear dark so that a doctor can identify them more easily.
T2-weighted scans: In a T2-weighted scan, a radiologist will administer different pulses through the MRI machine. Older lesions will appear a different color to newer lesions. Unlike on T1-weighted scan images, lesions appear lighter on T2-weighted images.
Fluid-attenuated inversion recovery (FLAIR): FLAIR images use a different sequence of pulses than T1 and T2 imaging. These images are very sensitive to the brain lesions that MS usually causes.
Spinal cord imaging: Using an MRI to show the spinal cord can help a doctor identify lesions that occur here as well as in the brain, which is important in making an MS diagnosis.
Some people may be at risk of an allergic reaction to the gadolinium that T1-weighted scans use. Gadolinium can also increase the risk of kidney damage in people who already have some decrease in kidney function.
What do the results mean?
The doctor will explain the results and what they mean.
A radiologist who specializes in interpreting images will analyze the results of an MRI scan. They will send these results to the person's doctor for further interpretation.
Aging can also cause people, particularly those older than 50 years, to develop small lesions on the brain that do not have an association with MS. While doctors can still use an MRI scan to try to establish whether someone older has MS, diagnosis may be more difficult.
MRI tests are important for diagnosing MS, but they are not the only tests that a doctor will use because MS lesions do not always appear on a scan.
What is the outlook for a person with MS? Find out more here.
Cerebrospinal fluid (CSF) evaluation: This test involves inserting a needle into the spinal canal and withdrawing CSF. The presence of specific proteins in the CSF can indicate that a person may have MS.
Evoked potential tests: An evoked potential test measures how a person's brain responds to certain stimuli. Examples of stimuli include flashing lights or electrical impulses that a doctor applies to the person's legs or arms. This test can help diagnose MS because it allows a doctor to detect how effectively and quickly a neurological impulse travels.
Learn more here about the tests for diagnosing MS.
Living with MS
A person who receives a diagnosis of MS will be able to discuss their treatment plan with a doctor.
They may need further MRI testing to collect more information that can help doctors decide on the best treatment methods and monitor the progression of the disease.
For example, if a doctor prescribes a particular treatment that aims to prevent symptoms from worsening, but a scan shows that lesions are becoming more pronounced, the person may need a different treatment.
The four main types of MS are:
Clinically isolated syndrome: Symptoms appear only once and then seem to go away.
Relapsing-remitting MS (RRMS): RRMS is the most common type, and it involves flares, during which symptoms get worse, and times of remission, when they go away almost completely before returning during a flare at a later date.
Primary progressive MS (PPMS): After appearing, the symptoms of PPMS become progressively more severe.
Secondary progressive MS (SPMS): At first, the person experiences a flare of symptoms followed by recovery. Then, however, symptoms appear again and gradually become worse.
Learn more here about the different types of MS.
Some newer drugs can reduce the risk of MS flares.
RRMS may respond to an emerging set of medications called disease-modifying therapies (DMTs).
DMTs aim to slow the progression of MS and include:
- beta interferons
- glatiramer acetate
- dimethyl fumarate
Some drugs are available as injections or oral medications, while others are infusions that a doctor will deliver at regular intervals.
Some of these medications can have adverse effects, but new treatment options are proving to be safer and more effective than the older ones. A doctor may speak to an individual about switching to a newer drug.
However, these medications are unlikely to help a person with a progressive form of MS.
Managing flares and symptoms
Other medications, such as corticosteroids, can reduce inflammation in the nerves and are useful for treating flares or symptoms that suddenly become severe. Steroids will not change the long-term outlook for a person with MS, but they can help improve their comfort and quality of life.
Complications that can arise include bladder and bowel problems, fatigue, pain, and weakness. A doctor can prescribe different drugs to help manage these symptoms.
If a person notices side effects or a worsening of their symptoms, they should make their doctor aware.
Lifestyle options and therapies
Physical, occupational, and other types of therapy can also improve mobility and quality of life with MS.
Following a healthful lifestyle, which includes eating a nutritious diet, doing regular exercise, and avoiding smoking, can help boost well-being and may prevent a worsening of MS and its complications.
Some common early signs of MS include vision loss, problems maintaining balance, numbness or tingling, and difficulty tolerating heat. If a person experiences these symptoms, they should see their doctor as soon as possible for an evaluation.
MS is a lifelong, progressive condition that can, in some cases, have severe symptoms.
However, most people with MS experience mild-to-moderate symptoms and continue to be mobile. A person with MS can expect to live as long as a person without MS, according to the National Institute of Neurological Disorders and Stroke.
Treatment and support are available to help a person manage their condition.
The development of medications for MS is advancing rapidly. In the future, new therapies, such as stem cell therapy, may provide ways of stopping the damage that MS causes and possibly reversing the course of the disease.
How does MS affect life expectancy? Find out more here.