A breast magnetic resonance imaging (MRI) scan is a type of imaging test that uses magnets and radio waves to check for abnormalities in the breast.
An MRI gives doctors the ability to see the soft tissues of the body.
Your doctor may ask you to undergo a breast MRI scan if he or she suspects there are abnormalities with your breasts.
It is used to examine a woman’s breasts when other imaging tests are inadequate or inconclusive, screen for women with a high risk of breast cancer, or monitor the progression of breast cancer and treatments.
Other reasons for getting a breast MRI include:
- dense breast tissue
- diagnosing breast cancer
- family history of breast cancer
- leaking or ruptured breast implant
- lump in the breast
- precancerous breast changes
Breast MRIs are meant to be used with mammograms. While breast MRIs can detect many abnormalities, there are some breast cancers that a mammogram can better visualize.
An MRI is considered a safer alternative to scans that use radiation, such as CT scans, for women who are pregnant. While the radiation levels in CT scans are safe for adults, they aren’t safe for developing fetuses.
There is no evidence to suggest that the magnetic fields and radio waves are in anyway harmful.
While safer, breast MRIs do carry a few considerations:
“False-positive” results: As the test does not always distinguish between cancerous and noncancerous growths, it can detect masses that appear cancerous when they are not. Biopsies are needed to confirm the results of the test.
Allergic reaction to contrast dye: MRIs use a dye injected into the bloodstream to make the images easier to see. The dye has been known to cause allergic reactions and serious complications for people with kidney problems.
Prior to your MRI, your doctor will explain the test and review your complete physical and medical history. During this time, tell your doctor about any medication you may be taking or any known allergies. Tell your doctor if you have any implanted medical devices as these can be affected by the test.
Tell your doctor if you have had prior allergic reactions to contrast dye, or if you have been diagnosed with kidney problems. Also, tell your doctor if you are pregnant, concerned you may be pregnant, or are breastfeeding. The tests aren’t considered safe for pregnant women, and nursing mothers should not breastfeed their children for about two days after the test.
It’s also important to schedule your MRI at the beginning of your menstrual cycle. The best time for this is between days seven and 14 of your monthly cycle.
As the MRI machine is in a tight, enclosed space, tell your doctor if you are claustrophobic. He or she may give you a sedative to help you relax. In extreme cases, your doctor may opt for an “open” MRI where the machine is not 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.
Prior to your scan, you will change into a hospital gown and remove all jewelry and body piercings.
If you’re using a contrast dye, an IV will be inserted into your arm so that the dye can be injected into your bloodstream.
In the MRI room, you will lay 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, including holding your breath. As they will be in a separate room watching monitors that are collecting images, these instructions will be given over a microphone.
You won’t feel the machine working, but there may be some loud noises, such as clacks or thuds, and possibly a whirring noise. The technician may give you earplugs.
The test typically takes between 30 minutes and an hour. Once the images have been recorded, you can change and leave.
A radiologist will review your breast MRI scans and give them to your doctor, who will review them at a later date.
MRI images are black and white images. Tumors and other abnormalities may appear as bright white spots. These are where the contrast dye has collected because of the enhanced cell activity.
If your MRI shows that a mass could be cancerous, your doctor will order a biopsy. This is the surgical removal of a small sample of tissue from the suspected lump. A biopsy confirms if the lump is cancerous.