A Patient's Guide to MRIs Fact Sheet
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What is an MRI?
Magnetic resonance imaging (MRI) is a painless test that produces clear, detailed images of internal organs and tissues inside the body without the use of X-rays. After the test is complete, the doctor will use the images to identify a variety of conditions that may exist.
How does an MRI work?
Patients are placed on a moveable table in a large cylinder shaped scanner with openings on both ends. A microphone inside allows patients to talk to the technologist performing the test. Once in the machine, a strong magnetic field is created around the patient while radio waves are directed toward the body. The radio signals are computer-processed and turned into images.
Why do you need an MRI?
MRI scans have the ability to locate and help diagnose tumors and other functional disorders. An MRI is commonly used to diagnose sports-related injuries to the knee, elbow and shoulder. An MRI is also used to scan the head, neck, spinal cord, heart, chest, pelvis and bladder as well as male and female reproductive systems.
Is an MRI safe?
There are no known risks with an MRI scan. Notify your physician if you have questions about your current medications interfering with the MRI or general questions about the MRI scan. The following conditions prevent the MRI scan from making an accurate reading. If you have any of these conditions, the physician needs to be made aware prior to the exam.
- Cerebral aneurysm clip (metal clip on a blood vessel in the brain)
- Cochlear (ear) implant for hearing impairment
- Metal in the eye or eye socket
- Implanted spine stabilization rods
- Heart pacemaker
- Severe lung disease (such as tracheomalacia or bronchopulmonary dysplasia)
- Gastroesophageal reflux
- Implanted insulin pump (for treatment of diabetes), narcotics pump (for pain medication), or implanted nerve stimulators ("TENS") for back pain
- Weight of more than 300 pounds
- Inability to lie on back for 30 to 60 minutes
Preparing for your MRI
If you have claustrophobia, fear of closed or narrow spaces, you may receive sedation and should discuss this with your physician. Remove all jewelry including watches and wedding bands, as well as possible medical devices such as eyeglasses and hearing aids. Remove all clothing articles with metal zippers, snaps, buttons or underwires.
After your MRI
You may go home immediately after the test, unless you were given sedative medicine. If you received a sedative, you must have a responsible driver take you home and stay with you for several hours after the test.