A breast magnetic resonance imaging (MRI) test is an imaging test that does not use radiation. It uses magnetic fields to capture multiple images of the breast tissue. These images are combined to create detailed pictures of the inside of your breasts.
Reasons a person might need a breast MRI
This test has many uses, including:
Screening women who are at a high risk for breast cancer (see below).
Finding and learning more about breast tumors. This test may be better at finding a small mass in a woman's breast than a mammogram or ultrasound. It is most helpful for women with very dense, non-fatty breast tissue.
Learning more about the stage of cancer. The stage is a way to describe the tumor’s size and if or where it has spread.
Looking for cancer in the opposite breast after an initial diagnosis of breast cancer
Monitoring how well chemotherapy is working
Examining the area where the cancerous breast tissue was removed as a part of follow-up care
Learning whether breast implants have torn or leaked, including in women who have had their breast(s) reconstructed with implants after a mastectomy
Breast MRI for cancer screening
Breast MRI is not recommended for routine screening for most women. However, it is recommended for women who have a higher risk of developing breast cancer. Breast MRI is not a replacement for mammography. Instead, it should be used as a complementary screening tool. For women at high risk for breast cancer, the American Cancer Society guidelines recommend having a breast MRI and mammogram every year.
This “high risk” group includes women who have at least one of the following:
A known BRCA1 or BRCA2 gene mutation OR a first-degree relative with a BRCA1 or BRCA2 gene mutation but have not had genetic testing themselves. A first-degree relative is a parent, brother, sister, or child.
A 20% or greater lifetime risk of breast cancer. This can be determined using a scientific tool that calculates a person’s lifetime risk of developing breast cancer. This information is primarily based on a person’s family history.
History of radiation therapy to the chest between the ages of 10 and 30. This type of radiation therapy is typically given for Hodgkin lymphoma.
A genetic mutation that increases the risk of breast cancer OR a first-degree relative with one of these syndromes. These syndromes include Li-Fraumeni syndrome, Cowden syndrome, or Bannayan-Riley-Ruvalcaba syndrome.
Women with a moderate risk of breast cancer should talk with their doctor about the best screening options for them.
Although it is a highly effective test, a breast MRI occasionally may fail to find cancer that a mammogram detects. Breast MRI does not show calcium deposits, known as calcifications or microcalcifications. These can be a sign of breast cancer and can be seen with mammography.
A breast MRI may also lead to a false positive result. This means that the test finds something that looks suspicious that turns out not to be cancer.
Finally, breast MRI is more expensive than mammography. Many insurance companies will not pay for breast MRI for women at average risk for breast cancer. And, some do not cover breast MRI for women at high risk.
Who will perform my breast MRI?
You may receive a breast MRI in a hospital or in an outpatient clinic. A radiology technologist will perform the test, which is interpreted by a radiologist. A radiologist is a medical doctor who performs and interprets imaging tests to diagnose disease. The radiology technologist is specially trained and certified to perform MRI scans but does not interpret them.
Scheduling a breast MRI
For best results, if you are premenopausal, your MRI should be scheduled during days 7 through 10 of your menstrual cycle. Be sure to discuss this with your doctor.
Preparing for a breast MRI
When you schedule your MRI, you will get detailed instructions on how to prepare. Here are some general suggestions:
Tell your doctor about all medications you are taking. You should also talk about any drug allergies or other medical conditions you have.
Tell your doctor if there is any chance that you may be pregnant.
If breastfeeding, you should discuss the test with your doctor. Breast MRIs done while a woman is breastfeeding may be more difficult to interpret. If breastfeeding, you will be asked to nurse or pump immediately before your MRI. A very tiny amount of contrast material (See “Before the exam” below) will go into the breast milk. However, it is such a tiny amount, that the American College of Radiology does not require that patients stop breastfeeding after their MRI scan. But, you can pump and discard your milk for 24 hours afterwards if you prefer.
Tell your doctor and the radiation technologist about any metal implants or metal fragments you have in your body. These can cause serious complications when exposed to the MRI’s strong magnetic pull. People with most pacemakers, brain aneurysm clips, and cochlear implants cannot have an MRI.
Consider asking whether you can bring music with you to the scan. Some facilities allow patients to listen to music through headphones during the examination. This may help you relax during the procedure.
Finally, you may be asked to sign a consent form. It states you understand the benefits and risks of the breast MRI and agree to have the test done. Talk with your doctor about any concerns you have about the procedure.
Before the exam
When you arrive for your breast MRI, you will need to remove jewelry or metal objects you are wearing. You may need to change into a hospital gown.
You will be given a contrast material called gadolinium through an intravenous (IV) line. A technologist, nurse or doctor will insert a small needle into a vein in your arm or hand. This needle is connected to tubing. A saline solution will flow through the IV line until the contrast material is injected at a specific point during the examination. The contrast will travel through your bloodstream and help to create a clearer picture of your breasts.
Patients having a breast MRI for a ruptured implant do not typically get contrast material.
For some people, the contrast material may cause an allergic reaction. It may also cause problems for patients with kidney or liver problems. For these reasons, tell your doctor about any health conditions you have.
A breast MRI is not painful. However, if you receive an IV, you may feel discomfort when the needle is inserted. The saline solution in the IV may cause a cool feeling at the injection site.
In addition, you will need to lie still for most of the scan, which could become uncomfortable. The loud sounds coming from the machine could also make you uncomfortable. You may be given earplugs or earphones to wear during the test.
If you are claustrophobic, meaning you have a fear of being in small spaces, tell your doctor. He or she may prescribe you medication that will help you to relax. You can take this medication before your appointment or bring it with you to the MRI facility. In addition, before beginning the examination, tell the technologist that you are claustrophobic, so they are aware of your concerns.
A technologist will help position you on a padded table with cushioned openings for your breasts. When you are in the correct position, the table will slide into the MRI machine. This machine looks like a large donut with a narrow, tunnel-like opening. Some facilities have less confining “short-bore” or “open” MRI machines. These machines can accommodate larger people and help prevent claustrophobia.
During the procedure
The exam table will slide through the hole in the center of the machine. You will need to lay very still during the breast MRI's various imaging sequences. You will know that the machine is taking images because you will hear extremely loud tapping and knocking sounds. You will be allowed to relax slightly between each imaging sequence but will need to maintain your body position as much as possible.
During the examination, the technologist will be in a nearby room, separated by a window. The technologist will be able to see you. You will be able to communicate at all times through an intercom system.
The technologist should be able to give you an estimate of how long the session will last before you begin.
When the procedure is complete, you may be asked to remain on the exam table while a radiologist reviews the images to determine if additional images are needed.
After the procedure
You can expect to resume your normal activities, including driving, after the breast MRI exam, unless you were given a sedative.
A radiologist will review the images from your breast MRI and send a copy of the report to your doctor. Your doctor will discuss the results with you when they are available.
Questions to ask the doctor
Before having a breast MRI, consider asking your doctor the following questions:
Do I need an order (prescription) to schedule the test?
Does my insurance provider need to authorize this test beforehand?
Who will perform the exam?
What will happen during the breast MRI?
How long will the procedure take?
What are the risks and benefits of having a breast MRI?
Is the imaging facility accredited to perform breast MRIs?
When will I learn the results?
Who will explain the results to me?
What further tests may be necessary, depending on the results?
RadiologyInfo: Breast MRI