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Diagnosing Multiple Sclerosis With MRI

Widespread use of MRI (magnetic resonance imaging) has revolutionized the ability to diagnose multiple sclerosis. Disease-related changes in the brain or spinal cord are detected by MRI in more than 90% of people suspected of having MS.

What Is MRI?

MRI is a test that produces very clear pictures of the human body without the use of X-rays. It uses a large magnet, radio waves and a computer to produce these images.

MRI can often detect damaged areas in the brain or spinal cord that would be missed by other imaging techniques such as a CAT scan.

Why Do I Need to Get an MRI?

To detect MS. MRI is considered the best test to help diagnose MS. However, 5% of people with MS do not have abnormalities detected on MRI, thus a "negative" scan does not completely rule out MS. In addition, some common changes of aging may look like MS on a MRI.
To track the progress of disease. Although they aren't widely needed, sometimes someone with MS will get repeat scans to determine how fast the disease is progressing.

Is the MRI Exam Safe?

Yes. The MRI exam poses no risk to the average person if appropriate safety guidelines are followed. Many people who have had heart surgery and people with the following medical devices can be safely examined with MRI:

Artificial joints
Staples
Many cardiac valve replacements (check with your doctor)
Disconnected medication pumps
Vena cava filters
Brain shunt tubes for hydrocephalus

Some conditions may make an MRI exam a bad idea. Tell your doctor if you have any of the following conditions:

Heart pacemaker
Cerebral aneurysm clip (metal clip on a blood vessel in the brain)
Pregnancy
Implanted insulin pump (for treatment of diabetes), narcotics pump (for pain medication), or implanted nerve stimulators ("TENS") for back pain
Metal in the eye or eye socket
Cochlear (ear) implant for hearing impairment
Implanted spine stabilization rods
Severe lung disease (such as tracheomalacia or bronchopulmonary dysplasia)
Gastroesophageal reflux (a common disease that causes heartburn)
Weigh more than 300 pounds
Not able to lie on back for 30 to 60 minutes
Claustrophobia (fear of closed or narrow spaces)

How Long Does the MRI Exam Take?

Allow two hours for your MRI exam. In most cases, the procedure takes 40 to 80 minutes; during that time, several dozen images may be taken.

What Happens Before the MRI Exam?

Personal items such as your watch, wallet (including any credit cards with magnetic strips that can be erased by the magnet), and jewelry should be left at home if possible or removed prior to the MRI scan. Secured lockers are available to store personal possessions.

What Happens During the MRI Exam?

You may be asked to wear a hospital gown during the MRI scan.

As the MRI scan begins, you will hear the equipment making a muffled thumping sound that will last for several minutes. Other than that sound, you should experience no unusual sensations during the scanning.

Certain MRI exams require an injection of a contrast material. This helps identify certain parts of the body on the scan images.

Feel free to ask questions and tell the technologist or doctor if you have any concerns.