What Is a Breast MRI?
A breast magnetic resonance imaging (MRI) scan is a type of
imaging test that uses magnets and radio waves to check for abnormalities in
An MRI gives doctors the ability to 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.
Why a Breast MRI Is Done
A breast MRI is used to examine your breasts when other imaging
tests are inadequate or inconclusive, to screen for breast cancer in women with
a high risk of developing the disease, and to monitor the progression of breast
cancer as well as the efficacy of its treatment.
Your doctor may also order a breast MRI if you have:
- dense breast tissue
- signs of 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.
The Risks of a Breast MRI
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
There is no evidence to suggest that the magnetic fields and
radio waves in a breast MRI are in anyway harmful.
While safer than CT scans, breast MRIs do carry a few
results: an MRI does not always distinguish between cancerous and
noncancerous growths, therefore it can detect masses that may appear cancerous
when they are not. You may need a biopsy to confirm the results of your test.
reaction to contrast dye: MRIs use a dye 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.
How to Prepare for a Breast MRI
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. 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. You should
also tell your doctor if you are pregnant, think you may be pregnant, or are
breastfeeding. Breast MRIs aren’t considered safe for pregnant women, and
nursing mothers should not breastfeed their children for about two days after
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 menstrual
The MRI machine is in a tight, enclosed space, so you should tell
your doctor if you are claustrophobic. The doctor 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
How a Breast MRI Is Performed
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 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
and when to hold your breath. The technician will be in a separate room,
watching monitors that are collecting images, and therefore these instructions
will be given over a microphone.
You won’t feel the machine working, but you may hear some loud
noises, such as clacks or thuds, and possibly a whirring noise. The technician
may give you earplugs.
The test may take up to an hour. Once the images have been
recorded, you can change and leave.
Results from a Breast MRI
A radiologist will review your breast MRI scan, dictate their
interpretation findings, and give the findings to your doctor, who will review
them upon receipt of results. Your doctor will be in touch to discuss your
results or to schedule a follow-up appointment.
MRI images are black and white images. 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 shows that a mass could be cancerous, your doctor
will order a biopsy as a follow-up test. This is the surgical removal of a
small sample of tissue from the suspected lump. A biopsy will help your doctor
learn if the lump is cancerous or not.