Share on Pinterest
RubberBall Productions/Getty Images

A breast MRI scan is a type of imaging test that uses magnets and radio waves to check for abnormalities in the breast.

An MRI lets doctors see the soft tissues within your body. Your doctor may ask you to undergo a breast MRI scan if they suspect there are abnormalities in your breasts.

In this article, we’ll cover the reasons why a breast MRI might be performed, as well as possible risks, how to prepare, and more.

A breast MRI is used to:

Your doctor may also order a breast MRI if you have:

Breast MRIs are meant to be used with mammograms. While breast MRIs can detect many abnormalities, the mammogram remains the standard screening tool for breast cancer.

There’s no evidence to suggest that the magnetic fields and radio waves in a breast MRI are in any way harmful. But if you’re pregnant and your case isn’t urgent, it’s best to avoid a breast MRI.

Here are a few more things you should keep in consideration:

  • “False-positive” results. An MRI doesn’t always distinguish between cancerous and noncancerous growths. Therefore, it can detect masses that may appear cancerous when they’re not. You may need a biopsy to confirm the results of your test. This is the surgical removal of a small sample of tissue from the suspected lump.
  • Allergic reaction to contrast dye. During an MRI, a dye is injected into your bloodstream to make the images easier to see. The dye has been known to cause allergic reactions, as well as serious complications for people with kidney problems.

Before your MRI, your doctor will explain the test and review your complete physical and medical history. During this time, you should tell your doctor about any medication you may be taking or any known allergies.

You should also tell your doctor if:

  • you have any implanted medical devices, as these can be affected by the test
  • you’ve had prior allergic reactions to contrast dye
  • you’ve been diagnosed with kidney problems
  • you’re pregnant, think you may be pregnant, or are breastfeeding

Breast MRIs aren’t considered safe during pregnancy, and people who are nursing shouldn’t breastfeed their children for about 2 days after the test.

It’s also important to schedule your MRI at the beginning of your menstrual cycle. The ideal time is between days 7 and 14 of your menstrual cycle.

The MRI machine is in a tight, enclosed space, so you should tell your doctor if you’re claustrophobic. They may give you a sedative to help you relax. In extreme cases, your doctor may opt for an “open” MRI, where the machine isn’t as close to your body. Your doctor can best explain your options.

An MRI machine encompasses a flat table that can slide in and out of the machine. The rounded, wheel-like part is where the magnets and radio waves emit from to produce images of your breast.

Before your scan, you’ll change into a hospital gown and remove all jewelry and body piercings. If the technician is using a contrast dye, they’ll insert an IV into your arm so that the dye can be injected into your bloodstream.

In the MRI room, you’ll lie on your stomach on a padded table. There will be depressions in the table where your breasts will rest. The technician will then slide you into the machine.

The technician will give you instructions on when to hold still and when to hold your breath. The technician will be in a separate room, watching monitors that are collecting images. Therefore, they’ll give you these instructions over a microphone.

You won’t feel the machine working, but you may hear some loud noises, like clacks or thuds, and possibly a whirring noise. The technician may give you earplugs.

The test may take up to 1 hour. Once the images have been recorded, you can change your clothes and leave.

A radiologist will review your breast MRI scan, dictate their interpretation of the findings, and give the findings to your doctor. Your doctor will review the radiologist’s findings and be in touch to discuss your results or to schedule a follow-up appointment.

MRI images are black and white. Tumors and other abnormalities may appear as bright white spots. These white spots are where the contrast dye has collected due to the enhanced cell activity.

If your MRI indicates that a mass could be cancerous, your doctor will order a biopsy as a follow-up test. A biopsy will help your doctor learn if the lump is cancerous or not.