Breast MRI (magnetic resonance imaging) is a test that should not be used to distinguish between benign (noncancerous) and malignant (cancerous) areas, in lieu of a breast biopsy. Due to false positive results, performing this test may increase the number of breast biopsies that need to be performed. It is not appropriate to utilize breast MRI to evaluate a suspicious breast mass, or to follow these breast masses over time. Although MRI may detect tumors in dense breast tissue, the presence of dense breast tissue is not a reason to have a breast MRI scan. Breast MRI scanning cannot detect tiny specks of calcium (known as microcalcifications), which account for half of the cancers detected by mammography.
Purpose of This Summary
This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about the treatment of breast cancer. It is intended as a resource to inform and assist clinicians who care for cancer patients. It does not provide formal guidelines or recommendations for making health care decisions.
Reviewers and Updates
This summary is reviewed regularly and updated as necessary by the PDQ Adult Treatment Editorial...
A breast MRI is safe. The test 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
Most heart valve replacements
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:
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
Uncontrolled gastroesophageal reflux (a condition causing severe heartburn)
In addition, tell your doctor if you:
Weigh more than 300 pounds
Are not able to lie on your back for 30 to 60 minutes
Have claustrophobia (fear of closed or narrow spaces)
How Long Is the Breast MRI Test?
Allow 1 1/2 hours for your breast MRI exam. In most cases, the procedure takes 45 to 60 minutes, during which time several dozen images may be obtained.
What Happens Before a Breast MRI?
Before a breast MRI, personal items such as your watch, jewelry, and wallet -- including any credit cards with magnetic strips (they will be erased by the magnet) -- should be left at home or removed. Hearing aids should be removed before the test, because they can be damaged by the magnetic field. Secured lockers are typically available to store personal possessions.
What Happens During a Breast MRI?
You will be asked to wear a hospital gown during your breast MRI.
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 that you receive an injection of a contrast material known as gadolinium. This helps identify certain anatomic structures on the scan images.
Feel free to ask questions or tell the technologist or your doctor if you have any concerns.
What Happens After a Breast MRI?
Generally, you can resume your usual activities and normal diet immediately after a breast MRI.
Your doctor will discuss the test results with you.