In diagnosing arthritis, a MRI (magnetic resonance imaging) scan can be helpful. A MRI scan is a test that produces very clear pictures of the human body without the use of X-rays. MRI uses a large magnet, radio waves, and a computer to produce these images.
Osteoarthritis (OA) causes joint pain and stiffness for 27 million Americans. Although there are many medications and treatments to ease OA symptoms, many patients with severe OA decide to have joint replacement surgery. In fact, nearly 700,000 Americans undergo hip or knee replacement each year. Another 23,000 have shoulder replacement surgery.
To detect arthritis. MRI can be helpful in evaluating joint damage, particularly damage to the spine, knee, or shoulder.
To track the progress of disease. In repeat scans, MRI can determine how fast the arthritis is progressing.
Is the MRI Exam Safe?
Yes. The MRI exam poses no risk to the average person if appropriate safety guidelines are followed. People who have had heart surgery and people with the following medical devices can be safely examined with MRI:
Surgical clips or sutures
Cardiac valve replacements (except the Starr-Edwards metallic ball/cage)
Disconnected medication pumps
Vena cava filters
Brain shunt tubes for hydrocephalus
Some conditions may make an MRI exam inadvisable. Tell your doctor if you have any of the following conditions:
Heart pacemaker (MRI may not interfere with modern pacemakers)
Cerebral aneurysm clip (metal clip on a blood vessel in the brain)
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
Bullet(s) or shrapnel in your body
Implanted spine stabilization rods
Women with an intrauterine device (IUD)
Severe lung disease (such as tracheomalacia or bronchopulmonary dysplasia)
Weight of 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 and produces about a dozen images.
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 anatomic structures on the scan images.
Feel free to ask questions and tell the technologist or doctor if you have any concerns.
What Happens After the MRI Exam?
After an MRI scan, your doctor will discuss the test results with you. Generally, you can resume your usual activities immediately.