An MRI is a test that produces very clear pictures of the human body without the use of X-rays. Instead, MRI uses a large magnet, radio waves, and a computer to produce these images.
Is MRI Examination Safe?
Yes. The MRI examination poses no risk to the average patient 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
- Artificial joints
- 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 examination not a good 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)
- 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)
- Severe acid reflux
- Weight of more than 300 pounds
- Not being able to lie on back for 30 to 60 minutes
- Claustrophobia (fear of closed or narrow spaces)
How Long Is the MRI Exam?
Allow 1 1/2 hours for your MRI exam. In most cases, the procedure takes 45 to 60 minutes, during which several dozen images may be taken.
What Happens Before the Exam?
Personal items such as your watch, wallet (including any credit cards with magnetic strips - should not be brought into the room with the MRI machine in it.The credit cards will be erased by the magnet), and jewelry should be left at home or removed prior to the MRI scan. Secured lockers should be available to store personal items.
What Happens During the Exam?
You will 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, which will last for several minutes. Other than the sound, you should notice no unusual sensations during the scanning.
Certain MRI exams require an injection of a dye (contrast material). This helps identify certain anatomic structures on the scan images.
Before the exam, feel free to ask questions and tell the technician or doctor if you have any concerns.
People who get anxious when in tight spaces (claustrophobic) may benefit from talking to their doctor before the procedure. Some options include taking a prescription medication before the procedure to relieve anxiety or having the exam done in one of the newer and less confining MRI units, called an open MRI, when available.
What Happens After the Exam?
You should be able to resume your usual activities immediately. Your doctor will discuss the test results with you.