Breast MRI

Breast MRI (magnetic resonance imaging) uses radio waves and strong magnets to make detailed pictures of the inside of the breast.

When is breast MRI used?

To help determine the extent of breast cancer: Breast MRI is sometimes used in women who already have been diagnosed with breast cancer, to help measure the size of the cancer, look for other tumors in the breast, and to check for tumors in the opposite breast. But not every woman who has been diagnosed with breast cancer needs a breast MRI.

To screen for breast cancer: For certain women at high risk for breast cancer, a screening MRI is recommended along with a yearly mammogram. MRI is not recommended as a screening test by itself because it can miss some cancers that a mammogram would find.

Although MRI can find some cancers not seen on a mammogram, it’s also more likely to find things that turn out not to be cancer (called a false positive). This can result in a woman getting tests and/or biopsies that end up not being needed. This is why MRI is not recommended as a screening test for women at average risk of breast cancer.

What you need to know about getting a breast MRI

Just as mammograms are done using x-ray machines specially designed for the breasts, breast MRI also requires special equipment. This MRI machine is called an MRI with dedicated breast coils. Not all hospitals and imaging centers have dedicated breast MRI equipment. If you are having a breast MRI, it’s important to have it at a facility with dedicated equipment, and that can do an MRI-guided breast biopsy (or partners with a facility that can).

MRI uses strong magnets instead of radiation to make very detailed, cross-sectional pictures of the body. An MRI scanner takes pictures from many angles, as if someone were looking at a slice of your body from the front, from the side, or from above your head. MRI creates pictures of soft tissue parts of the body that would sometimes be hard to see using other imaging tests.

Tips for getting ready for the test

Check with your insurance provider before getting an MRI: Breast MRI costs a lot, and it may need to be approved by your insurance company before the scan is done. Most private insurance plans that pay for mammogram screening also pay for MRI as a screening test if a woman can be shown to be at high risk. It might help to go to a center with a high-risk clinic, where the staff has experience getting approval for breast MRIs.

Follow all instructions: You don’t usually need a special diet or preparation before an MRI, but follow any instructions you’re given.

If you have trouble with enclosed spaces: Breast MRI is most often done while you are lying on your belly inside a long, narrow tube. If being in a tight space might be a problem for you (you have claustrophobia), you might need to take medicine to help you relax while in the scanner. Talking with the technologist or a patient counselor or getting a tour of the MRI machine before the test can also help. You’ll be in the exam room alone, but you can talk to the MR technologist, who can see and hear what’s going on.

Remove metal objects: Before the test, you'll be asked to undress and put on a gown or other clothes without zippers or metal. Be sure to remove any metal objects you can, like hair clips, jewelry, dental work, and body piercings.

If you have metal in your body: Before the scan, the technologist will ask you if you have any metal in your body. Some metallic objects will not cause problems, but others can.

If you have any of these types of medical implants, you should not even enter the MRI scanning area unless you're told it's OK to do so by a radiologist or technologist:

  • An implanted defibrillator or pacemaker
  • Clips used on a brain aneurysm
  • A cochlear (ear) implant
  • Metal coils inside blood vessels

illustration showing woman as she gets a breast mri

What’s it like to get a breast MRI?

MRI scans are usually done on an outpatient basis in a hospital or clinic. You’ll lie face down on a narrow, flat table. Your breasts will hang down into an opening in the table so they can be scanned without being compressed. The technologist may use pillows to make you comfortable and help keep you from moving. The table then slides into a long, narrow tube.

The test is painless, but you have to lie still inside the narrow tube. You may be asked to hold your breath or keep very still during certain parts of the test. The machine may make loud, thumping, clicking, and whirring noises, much like the sound of a washing machine, as the magnet switches on and off. Some facilities give you earplugs or headphones to help block noise out during testing.

The most useful MRI exams for breast imaging use a contrast material called gadolinium that’s injected into a vein in the arm before or during the exam, which helps to clearly show breast tissue details. (This is not the same as the contrast dye used in CT scans.) Let the technologist know if you have any kind of allergies or have had problems before with any contrast or dye used in imaging tests.

It’s important to stay very still while the images are being made.

Each set of images usually takes a few minutes, and the whole test usually takes between 45 and 60 minutes. After the test, you may be asked to wait while the pictures are checked to see if more are needed.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Esserman LJ, Joe BN. Diagnostic evaluation of women with suspected breast cancer. UpToDate. 2019. Accessed at https://www.uptodate.com/contents/diagnostic-evaluation-of-women-with-suspected-breast-cancer on August 22, 2019.

National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology.
Breast Cancer. Version 2.2019. Accessed at https://www.nccn.org/professionals/physician_gls/pdf/breast.pdf on August 22, 2019.

Slanetz PJ. MRI of the breast and emerging technologies. UpToDate. 2019. Accessed at https://www.uptodate.com/contents/mri-of-the-breast-and-emerging-technologies on August 23, 2019.

Weinstein SP, Roth SO. Chapter 12: Imaging Analysis: Magnetic Resonance Imaging. In: Harris JR, Lippman ME, Morrow M, Osborne CK, eds. Diseases of the Breast. 5th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2014.

Last Medical Review: October 3, 2019 Last Revised: October 3, 2019

American Cancer Society medical information is copyrighted material. For reprint requests, please see our Content Usage Policy.