What Is an MRI Scan?
An MRI -- magnetic resonance imaging -- scan is a test that produces very clear pictures, or images, of the human body without the use of X-rays. For someone with epilepsy, a scan may help determine the cause.
Is MRI Safe?
Yes. The MRI exam poses no risk to the person if appropriate safety guidelines are followed.
Most heart surgery patients and patients with the following medical devices can be safely examined with MRI:
- Surgical clips or sutures
- Artificial joints
- Most heart valve replacements
- Disconnected medication pumps
- Vena cava filters (after six weeks for certain types)
- 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.
- Cerebral aneurysm clip (metal clip on a blood vessel in the brain). Most modern clips are made of titanium and can be safely studied.
- 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.
- Older implanted spine stabilization rods. New ones are titanium and safe.
- Severe lung disease (such as tracheomalacia or bronchopulmonary dysplasia).
- Not able to lie on back for 30 to 60 minutes.
- Claustrophobia (fear of closed or narrow spaces). If this condition applies to you, you can receive sedation during the exam if prior arrangements have been made.
If you weigh more than 300 pounds you may require a special machine that has a larger opening.
How Long Is the MRI Exam?
In most cases, an MRI exam takes 30 minutes but can take longer if special studies are needed. During the test, several dozen images may be obtained.
Before an MRI Exam
Personal items such as your watch, wallet, including any credit cards with magnetic strips (they will be erased by the magnet), and jewelry should be left at home if possible, or removed prior to the MRI scan. Secured lockers are usually available to store personal possessions.
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 which will last for several minutes. Other than the sound, you should experience no unusual sensations during the scanning.
Certain MRI exams require an injection of a contrast material called gadolinium. This helps identify certain structures on the scan images.
Please feel free to ask questions. Tell the technologist or your doctor if you have any concerns.
After the MRI Exam
Generally, you can resume your usual activities and normal diet immediately after an MRI scan.
The results of your MRI should be available to your doctor within 24 hours after your test, Monday through Friday. Your doctor will discuss the test results with you. Many facilities will give you a CD that contains the study that you can carry to your doctor.