Magnetic resonance imaging (MRI) is a painless test which uses magnetic fields, radio waves and a computer to produce detailed pictures of the breast. A breast MRI shows structures of the breast in a way that may not be shown by a mammogram or ultrasound.
Who needs a breast MRI?
A breast MRI may be ordered by your provider in the following circumstances:
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Breast screening if you are at high risk for breast cancer (typically as a result of your family’s history of breast cancer or ovarian cancer). If you are unsure whether or not you are considered high risk, ask your health care provider to help you determine your personal risk estimate.
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Determining the extent of cancer after a new diagnosis of breast cancer
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Looking more closely at hard-to-assess areas identified on a prior mammogram. This can be used to determine whether or not to do a breast biopsy (a sampling of a small amount of breast tissue for laboratory testing)
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A suspected leak or rupture of a breast implant
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You have dense breast tissue which makes accurate mammography difficult
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You have had radiation treatments to your chest before age 30
What to expect during a breast MRI:
Schedule your MRI for the beginning of your menstrual cycle (7-14 days after the first day of menstrual bleeding).
MRI’s are not usually recommended for women who are pregnant.
A breast MRI involves injection of a dye to help make the pictures of the breast easier to read. This dye can rarely cause allergic reaction or serious complications for people with kidney disease.
If you are breastfeeding, your health care provider may recommend that you stop nursing for two days after your MRI, although the American College of Radiology states that the risk to a newborn baby from any contrast dye in its mother’s breastmilk after having a breast MRI is extremely low.
A breast MRI is a safe procedure and does not use x-rays.
The MRI machine has a large, central opening and during the breast MRI, you lie face down on a padded scanning table. If you have trouble being in a small, confined space, tell your health care provider before your breast MRI. You may be given a mild sedative. During the MRI, you may hear loud tapping and thumping sounds coming from inside the machine. You may be given earplugs to wear.
During the test, the MRI technologist monitors you from another room and you can speak to the technologist through a microphone. You’ll be instructed to breathe normally, but lie as still as possible.
A breast MRI appointment may take 30 minutes to one hour.
Breast MRI results
A doctor specializing in imaging techniques (radiologist) reviews the images from your breast MRI, and a member of your health care team will contact you to discuss the results of the test.
A breast MRI may identify suspicious areas that, after further evaluation (breast biopsy or breast ultrasound) turn out to be normal (benign). Such false results are called false positives and can lead to unneeded anxiety and the need to undergo additional testing.
A breast MRI adds information but does not replace mammograms or other breast screenings.