How Radiology Is Used to Diagnose Multiple Sclerosis

MRI Is a Sensitive and Essential Diagnostic Tool

Multiple sclerosis (MS) is an unpredictable disease in which a person's immune system damages the protective myelin coating of nerves within the central nervous system (CNS). The CNS is made up of your brain, spinal cord, and the optic nerves of your eyes.

Diagnosing MS has traditionally been a challenging task because symptoms are often subtle and can mimic those of other health conditions. There's also no single test that can confirm a diagnosis of MS. The emergence of advanced magnetic resonance imaging (MRI) techniques, however, has revolutionized the detection of MS.

This article will review how different types of MRI scans can help support an MS diagnosis. It also will explore what it's like to undergo an MRI and provides some basic information on the cause, types, diagnosis, and treatment of MS.

Imaging technician talks to person about to have MRI

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What Is Multiple Sclerosis?

In MS, a person's immune system mistakes myelin in the CNS for a foreign invader and launches attacks to damage and destroy it. During such attacks, fighter cells (called T cells) break through the blood-brain barrier (BBB).

What Is the Blood-Brain Barrier?

Your blood-brain barrier is a tightly joined layer of cells intended to prevent foreign substances from entering the brain.

Once in the CNS, the T cells damage myelin (a process called demyelination), causing lesions (areas of inflammation) to form. Depending on their location, these lesions can lead to an array of MS symptoms.

Types

Experts have identified four types of MS, which are:

  • Clinically isolated syndrome (CIS) occurs when a person experiences their first episode of symptoms caused by damaged myelin in the CNS. Those diagnosed with CIS may or may not go on to develop MS. 
  • Relapsing-remitting MS (RRMS) is the most common type of MS and is characterized by relapses of new or worsening MS symptoms. After a relapse, symptoms go away or improve.
  • Secondary progressive MS (SPMS) occurs when a person with RRMS transitions to a progressive form of MS in which symptoms slowly worsen over time. Occasional relapses may still occur in SPMS.
  • Primary progressive MS (PPMS) affects around 15% of those with MS and is associated with worsening symptoms and disability from the start of the disease. Relapses do not occur in PPMS. Spinal cord symptoms like walking or bladder problems are also common.

Radiology for MS Diagnosis

Magnetic resonance imaging (MRI) is a noninvasive imaging technology that creates three-dimensional images of the body's soft tissues. Magnetic fields and radio waves (not radiation) are used to produce these images.

MRI is the most sensitive test for detecting MS-related inflammation and damage in the tissues of the central nervous system.

Different types of MRIs can be used, depending on whether neurologists (specialists in conditions affecting the nervous system) are diagnosing or monitoring MS.

With some types of MRIs, a person is injected with a contrast dye called gadolinium. As a large molecule, gadolinium cannot normally pass the blood-brain barrier. However, when a person's MS is active, the blood-brain barrier is disrupted, allowing for it to enter and light up any inflamed areas.

Risks and Contraindications

MRI is rarely associated with any risks or adverse effects. Conditions or issues that may affect your safety and/or prevent you from undergoing the MRI include:

  • Medical implants and devices: Before getting an MRI, you will be carefully screened for any metal or electrical implants, devices, or foreign bodies to ensure you are "MRI safe." This checklist includes pacemakers, artificial heart valves, metal joint prostheses, nerve stimulators, cochlear implants, bullet fragments, and any stents, ports, staples, or coils.
  • Use of contrast: If gadolinium is used, there is a risk of developing a rare but serious condition called nephrogenic systemic fibrosis. People with severe kidney impairment are at the highest risk of developing this complication. As a result, a blood test to check your kidney function may be performed prior to undergoing an MRI with contrast.
  • Pregnancy: The risks presented to a developing fetus by MRI are unknown, although experts suspect they are low. The possible benefit of undergoing the MRI should justify any potential risk to the baby. Also, gadolinium is not recommended in pregnant people, as it can cross the placenta.
  • Poor candidate: People who may not be able to remain still during the procedure or are claustrophobic may require sedation to undergo an MRI.

Types of MRIs

The different types of MRIs used to evaluate MS include:

  • T1-weighted brain MRI with gadolinium detects bright/white spots that represent areas of active inflammation (enhancing lesions).
  • T1-weighted brain MRI without gadolinium detects dark spots ("black holes") thought to represent permanent nerve damage.
  • T2-weighted brain MRI measures lesion burden ( the total number of both old and new lesions). It's often used to monitor disease progression in MS by comparing results over time.
  • Fluid-attenuated inversion recovery (FLAIR) sequences are ideal for detecting bright/white MS lesions because they suppress interference from the cerebrospinal fluid (the fluid surrounding the brain and spinal cord). They are especially sensitive in detecting bright/white spots in the periventricular region of the brain (a common area affected by MS).
  • Spinal cord MRI is used to identify MS-related damage in the spinal cord (as opposed to the brain or optic nerves). Spinal cord abnormalities can provide additional support for an MS diagnosis.

T1, T2, and FLAIR are often done in sequence in a single examination.

Are CT Scans Helpful for Diagnosing MS?

A computed tomography (CT) scan is not used to diagnose MS; although it can be helpful in ruling out alternative diagnoses. Overall, MRIs are significantly more sensitive in detecting abnormalities within the brain and spinal cord tissue.

What to Expect

MRIs are performed in a hospital or freestanding imaging facility. Beforehand, discuss whether you will be able to drive after the procedure. If you are given a sedative, you will need someone else to drive you home.

Before the Test

Once you arrive for your MRI, you will fill out a healthcare form and be asked to remove anything with metal, including keys, jewelry, body piercings, and cell phones.

You may be asked to change into a hospital gown or be allowed to wear your own clothes, assuming they contain no metal (e.g., sweatpants with an elastic waist).

When the MRI technician is ready, you will be asked to lie flat on a bed. You will be given earplugs or a headset to help reduce the noise of the MRI scanner. Patients who are claustrophobic or unable to lie still may receive a sedative to help them relax during the test.

Once you are comfortable, the technician will electronically move the bed back into a magnetic tube-like structure.

During the Test

While the MRI is performed, your technician will oversee the images in an adjoining room. You will be able to talk with your technician via an intercom system throughout the test.

If you are receiving gadolinium, you may have an intravenous (IV) catheter placed in your arm before the MRI or halfway through the test.

The length of your test will depend on whether you are undergoing both a brain MRI and a spinal cord MRI and if contrast is being administered.

After the Test

When the MRI scan is complete, the technician will move the table out of the tubelike structure. They will remove your IV (if one was placed) and help you up from the table.

You will be able to get dressed and go home. If you received a sedative, you will not be allowed to drive and will need a family member or friend to drive you home.

Interpreting Results

After you undergo an MRI, a neuroradiologist (a doctor who specializes in interpreting imaging tests of the nervous system) will look for areas of myelin or nerve fiber damage within the tissues that were scanned.

For example, on a T1-weighted MRI with gadolinium, areas of active inflammation will show up as bright white spots. These enhancing lesions indicate that myelin damage and scarring are currently (or recently) occurring.

The neuroradiologist will then type up a formal report of their findings and relay that report to the ordering provider.

Keep in Mind

Not all enhancing lesions indicate MS. They may stem from normal aging, or another neurological condition, like migraine. This is why multiple tools, in addition to a clinical exam, are used to diagnose MS.

Other MS Diagnostic Tests

Neurologists use a formal set of guidelines called the McDonald criteria to diagnose MS.

Fulfilling the McDonald criteria means that a person has evidence of MS-related damage to their CNS at different dates and to different parts (referred to as "dissemination in time and space").

Besides asking you questions about your symptoms, performing a neurological exam, and using data from your MRI, a doctor will use the information gathered from one or more of these other tests is often used to help make a diagnosis of MS:

  • Spinal tap (lumbar puncture): Cerebrospinal fluid is removed from the spinal canal and tested for inflammation-related proteins commonly found in patients with MS called oligoclonal bands.
  • Laboratory studies: Used to rule out conditions that may mimic MS, like vitamin B12 deficiency or Lyme disease.
  • Evoked potential tests: Wires are placed on the scalp over specific areas of the brain. Responses of the brain to different sensory stimuli (e.g., flashing lights) are recorded.

Treatment

MS is an incurable disease. However, there are disease-modifying therapies (DMTs) that can slow the disease down and reduce the number and severity of MS relapses.

There are numerous DMT options, and they vary in their delivery method (oral vs. injection vs. infusion), mode of action, level of effectiveness, and side effect profiles.

There are also medications, rehabilitation therapies, and/or complementary or alternative therapies that can ease MS symptoms and help you feel better on a day-to-day basis.

Finally, MS researchers are hard at work examining stem cell transplantations. These treatments could either promote myelin repair or possibly put patients into long-term remission by rebuilding their immune systems.

Living With MS

No two people with MS experience the disease in the same way. As such, it's best not to compare your symptoms, disease course, or treatment plan with others. Instead, focus on optimizing your quality of life through self-compassion and a take-charge attitude.

Consider the following strategies:

  • Be open and honest with your MS care team about your symptoms and concerns regarding your treatment plan, and continue with your medication unless otherwise instructed by your neurologist.
  • Create an action plan for your bad days with MS, which may involve having a loved one or neighbor on-call in case you need help with chores, child or pet care, or preparing meals.
  • Take care of your overall health and well-being, including by eating nutritiously, staying as active as possible, and taking time every day to unwind and relax.

How to Know If You Have MS

If you think you may have MS, the first medical professional to see is your primary care provider. Your provider will ask you questions about how you are feeling and perform an exam. Depending on their suspicions and clinical findings, they may also order various blood and imaging tests.

If you are referred to a neurologist, try to see an MS specialist (a physician with experience detecting and diagnosing MS).

Know that whether MS is ruled out or in, the diagnostic process can be time-consuming and nerve-racking. During this trying time, don't hesitate to ask questions, communicate your concerns, and lean on family members and friends for comfort and emotional support.

When to See a Healthcare Provider

The symptoms of MS, especially early on, can be subtle and resemble those of other medical conditions.

While not an exhaustive list, possible MS symptoms include:

  • Vision changes (e.g., blurry or double vision)
  • Numbness and tingling
  • Muscle weakness or paralysis
  • Imbalance
  • Headache
  • Unusual fatigue

See your healthcare provider if you are experiencing any of the above or if your symptoms are bothersome or interfering with your ability to function.

Summary

The diagnosis of MS requires a medical history, neurological exam, and blood/spinal fluid tests. An MRI is also essential for detecting MS-related abnormalities in the brain and spinal cord. There are different types of MRIs, depending on the purpose of the test (diagnosis versus monitoring), and whether injected contrast dye is being used.

If you or your primary healthcare provider believes you have the symptoms of MS, arrange to see a neurologist who specializes in MS care. This is because MS is a complex disease that affects people uniquely. It requires a thorough evaluation to avoid misdiagnosis and an individually tailored treatment plan.

A Word From Verywell

If you or a loved one has been recently diagnosed with MS, know that you are not alone. Reach out to loved ones for support, and learn as much as you can about the disease. Consider gaining knowledge through content written or vetted by board-certified physicians, as on Verywell Health, or through resources provided by the National MS Society.

Frequently Asked Questions

  • Can radiation cause multiple sclerosis?

    Available research suggests that radiation does not lead to the development of MS. However, radiation could possibly trigger a relapse in people with MS.

  • What is an MRI?

    An MRI is the most sensitive, noninvasive way of diagnosing MS-related damage in the brain, spinal cord, and eyes' optic nerves. Instead of radiation, MRIs use magnetic fields and radio waves to detect areas of active inflammation or nerve damage.


  • What does MS look like on CT scans?

    A CT scan is not used to diagnose MS, with the exception of ruling out alternative diagnoses. That said, areas of demyelination (loss of the fatty myelin sheath covering nerve fibers) are sometimes seen on the CT scan of a person with MS. Nevertheless, MRI offers a much more sensitive means of detecting MS-related changes.

  • Do radiologists diagnose MS?

    Neuroradiologists interpret the findings of a patient's MRI, which is the most sensitive test for detecting MS-related inflammation. However, neurologists formally diagnose MS. In addition to using data from a person's MRI, they look at results from other studies (e.g., laboratory tests and spinal tap) when making the diagnosis.

 

 

 

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