MRI (magnetic resonance imaging) is a test that produces very clear images of the brain without the use of X-rays. MRI uses a large magnet, radio waves, and a computer to produce these images. A MRI scan can provide information about the structure and biochemistry of the brain in hopes of finding the cause or causes of your migraines or headaches.
Why Is MRI Used to Evaluate Headaches?
A MRI scan may be recommended if you are getting daily or almost daily headaches. MRI may also be recommended if a CT SCAN does not show definitive results. In addition, a MRI scan is used to evaluate certain parts of the brain that are not as easily viewed with CT scans, such as the spine at the level of the neck and the back portion of the brain. A MRI scan is not able to diagnose migraines, cluster, or tension headaches; however, it is able to rule out other medical conditions, such as:
- Brain tumor
- Abscess (infection)
- Hydrocephalus (the abnormal buildup of fluid in the brain)
- Spinal cord problems, such as a herniated disc
Is a MRI Scan 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
- 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 a MRI exam inadvisable. Tell your doctor if you have any of the following:
- Heart pacemaker
- Cerebral aneurysm clip (metal clip on a blood vessel in the brain)
- Are pregnant
- Implanted insulin pump (for treatment of diabetes), narcotics pump (for pain medication), or implanted nerve stimulators
- “TENS” device 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 (GERD)
- Weigh more than 300 pounds
- Not able to lie on back for 30-60 minutes
- Claustrophobia (fear of closed or narrow spaces)
How Do I Prepare for the MRI Scan?
- Allow about two hours for your MRI exam. In most cases, the procedure takes 40 to 80 minutes, during which several dozen images may be obtained.
- 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.
What Happens Before the MRI Scan?
Sometimes, mild sedation is given to make you feel relaxed and drowsy before your MRI scan.
What Happens During the MRI Exam?
- You may be asked to wear a hospital gown during the MRI scan. If you are noise sensitive, ask for ear plugs.
- As the MRI scan begins, you will hear the equipment making a muffled thumping sound that 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. This helps identify certain anatomic structures on the scan images.
- Feel free to ask questions. Tell the technologist or the doctor if you have any concerns.
What Happens After My MRI Exam?
- Generally, you can resume your usual activities and normal diet immediately following a MRI test.