Breast Magnetic Resonance Imaging (MRI)

Advantages of breast MRI

Breast MRI is very sensitive for detecting breast cancer. Most women will have a mammogram to screen for breast cancer. If you are at a higher risk for caner, your doctor may order a breast MRI as an additional screening option. Breast MRI also can be used to look for additional cancer if you have been recently diagnosed with breast cancer. However, MRI does not replace mammography, and most patients who have a breast MRI will have a mammogram as well.

Breast MRI technique

During a breast MRI, a liquid (contrast agent) is given intravenously (IV) through a vein, usually in your arm. The contrast agent allows radiologists to look at how areas in the breast enhance or "light up" and decide if additional testing is needed.

How breast Magnetic Resonance Imaging (MRI) is used

There are many reasons why your doctor may order a breast MRI. The two most common reasons are:

High-risk screening

Breast MRI is an additional way to screen the breasts for cancer (with a mammogram) in patients at high risk for breast cancer. If you are uncertain if you are at high risk for developing breast cancer, the UW Health PATHS Clinic (Prevention, Assessment, and Tailored Health Screening) can help. Guidelines from the American Cancer Society and the National Comprehensive Cancer Network help doctors decide which women will most likely benefit from breast MRI and mammography to screen for breast cancer. Your doctor can help you determine if you are at a higher risk for breast cancer and if breast MRI would be a good additional test for you.

New diagnosis of breast cancer

Breast MRI can help patients who have been recently diagnosed with breast cancer and their doctors decide the best treatment and surgery options. If you have been recently diagnosed with breast cancer, your doctor may order a breast MRI to look for additional cancer in the same breast or a cancer in the opposite breast. Patients having chemotherapy before surgery (neoadjuvant chemotherapy) may have breast MRI to see if the cancer is changing in response to the chemotherapy. Finally, patients with cancer in the lymph nodes under their armpit (axillary lymph nodes) that might be breast cancer, but have a normal mammogram, may have a breast MRI to see if breast cancer can be found.

Other reasons to have a breast MRI include following up on a previous imaging study or looking to see if silicone breast implants are ruptured. If breast MRI is used to look at implants and not for breast cancer, a contrast agent is not needed.

Breast Magnetic Resonance Imaging (MRI) preparation and procedure

Preparing for Breast MRI

Patients who are pregnant or breastfeeding should tell their doctor before scheduling a breast MRI.

Before any type of MRI, you will need to answer some questions that ask if you have any metal in your body, such as cardiac pacemakers and defibrillators, brain aneurysm clips, prosthetic devices and other metallic implants. Although many of the medical metallic implants are safe to go into an MRI scanner, some are not. Also, patients who are or have been welders or sheet metal workers, or might have shrapnel in their body may need additional tests to make sure that it is safe for them to have an MRI. The nurses, radiologists and MRI technologists involved in your procedure will help you answer these questions and decide if the MRI is safe for you.

You will need to undress from the waist up for the breast MRI. A gown will be provided, and an intravenous (IV) needle will be placed in a vein in your arm. You will be asked to remove any jewelry, keys, credit cards, watches or other metallic objects and secure them in a safe location that we will provide for you.

The breast MRI exam

Before the MRI, the technologist will give you earplugs and have you lie on your stomach on a special table for patients having a breast MRI. Padding and a head rest are provided to make sure you are comfortable during the MRI exam. The table will move into the MRI scanner, and during the imaging you will hear dull pounding and clicking sounds coming from the scanner. This is normal. You will be able to speak to the MRI technologist through a microphone, and he or she will tell you what is happening throughout the exam. It is very important that you do not move during the MRI, which will take about 30 minutes.

Images will be taken before and after a liquid (contrast agent) is given through the IV. Some patients cannot have the gadolinium contrast used for MRI because of an allergy or because their kidneys do not work normally. If that is the case, a breast MRI will not be performed because it requires IV contrast.