What is a breast MRI?
A breast MRI is a painless imaging exam. It stands for magnetic resonance imaging. An MRI uses large magnets, radio waves, and a computer to produce images of body structures. MRI images are very detailed and provide doctors with information not available with standard mammogram X-rays or breast ultrasounds. Sometimes, doctors order a contrast agent or dye during the procedure to increase the image clarity even more. A breast MRI can help doctors diagnose breast conditions, including breast cancer. Another name for this test is a breast MRI scan.
Why is a breast MRI performed?
An MRI for a breast cancer evaluation is currently the most common reason to have a breast MRI. But there are also other reasons to have a breast MRI. Your doctor may recommend a breast MRI for the following:
Determining the extent of cancer after a new breast cancer diagnosis. This includes finding out whether the cancer has spread to the underlying muscles or if there are suspicious lymph nodes.
Evaluating a breast tumor when planning surgery to remove it. This includes looking for other areas of cancer in the same breast and in the opposite breast. It is also useful for women who have chemotherapy before surgery in a effort to shrink the tumor.
Evaluating an abnormality from another imaging exam, such as a mammogram or breast ultrasound.
Evaluating an old lumpectomy site when something changes on a mammogram or ultrasound. An MRI can tell doctors if the change is due to normal scar aging or if it is a cancer recurrence.
Evaluating silicone breast implants to see if the implant has ruptured.
Screening women who are at high risk of breast cancer or have dense breast tissue. MRI screening is a supplemental exam that can complement mammography. MRI can find some cancers that a mammogram could miss. However, it can also miss certain cancers that would show up on a mammogram.
Who performs a breast MRI?
An MRI technologist will perform your breast MRI. This healthcare provider has the training to run the exam, but will not be able to give you results. A radiologist will interpret the results. A radiologist is a doctor with advanced training in reading imaging tests, including ultrasounds, X-rays, and MRIs. Your doctor will receive a report from the radiologist and share the findings with you.
How is a breast MRI performed?
Breast MRIs take place in hospital radiology departments or MRI centers. The test can take up to an hour.
What to expect the day of your breast MRI
In general, this is what happens the day of your procedure:
You will change into a hospital garment that opens in the front. You will need to remove all jewelry, hair accessories, and loose objects or devices. You cannot take anything with metal into the MRI room.
If your exam involves a contrast agent, the technologist will place a catheter into a vein (an intravenous, or IV catheter) in your arm or hand.
You will lie facedown on a padded MRI table. There will be special openings at your chest level to let your breasts hang down. The technologist will position your breasts for optimal scanning. This does not involve any compression, so it will not hurt. Make sure you are comfortable because you must remain completely still during the exam.
The technologist will give you earplugs or ear protection. This will help dampen the loud noises of the magnet, such as thumps and clicks. The magnet will also produce vibrations you can feel.
The MRI table will slide into the cylinder-shaped MRI tube. Women who suffer from claustrophobia may have a light sedative. This will help you stay relaxed and still.
The technologist will leave the room to start the MRI. The technologist will see you at all times through a window. You will be able to hear the technologist through a speaker. However, you should not talk during the exam. Talking creates small chest movements that can interfere with the images. You have access to an emergency call button if necessary.
You will need to take regular, even breaths during the exam. The machine can adjust to your regular even breathing to create clear images.
Once the exam is complete, you wait briefly while the technologist checks the images. Then, the technologist will remove your IV and take you to change clothes.
You can go home right after a breast MRI. If you were given a sedative, you may need someone to take you home.
What are the risks and potential complications of a breast MRI?
A breast MRI is generally a safe procedure with very few risks. An MRI does not expose you to radiation. There are no known harmful side effects of the brief exposure to the strong magnetic field it uses. However, allergic reactions to contrast agents or dyes can happen in rare instances. People with kidney disease may also rarely have worsening kidney function with contrast agents.
With breast MRI, it is common for the test to find changes that turn out not to be cancer. This is a false-positive result. When something shows up on an MRI, doctors must order additional testing to find out if it is cancerous. This means women may undergo more biopsies and other tests after breast MRI than other imaging exams. This is a main reason why breast MRI screening is not for women at average risk of breast cancer.
How do I prepare for a breast MRI?
Part of preparing for an MRI includes scheduling the appointment, which is slightly different for premenopausal and postmenopausal women. Women who have not gone through menopause need to consider their menstrual cycle. The best time to have a breast MRI is during days 7 to 15. Call in advance—such as day 1, the day your period starts—so that the appointment falls during days 7 to 15.
Other steps you can take to prepare include:
Answering all questions about your medications, allergies, and medical history, especially kidney disease. Medications include prescription medications, over-the-counter drugs, herbal treatments, and vitamins.
Informing your technologist or doctor about all internal and external medical devices you have. This includes pacemakers, artificial joints, metal clips, and medication patches. These devices can malfunction or heat up causing burns during the MRI.
Leaving all jewelry and metal objects at home. Any loose metal object may cause damage or injury if it is pulled toward the magnet.
Telling your doctor and your technologist if you have claustrophobia or feel nervous or anxious about lying still or having the MRI.
Telling your doctor if there is any possibility you may be pregnant or if you are breastfeeding. You doctor may not advise an MRI during pregnancy. You may need to wait for a period of time after an MRI to breastfeed.
Telling your doctor and technologist about any tattoos or tattooed eyeliner, which may cause skin or eye irritation.
Questions to ask your doctor
If you have questions, make a list of the things you want to ask. Questions you may want to as your doctor include:
Why do I need a breast MRI? Are there any other options for diagnosing or screening my condition?
Will I need contrast for my MRI?
How long will the procedure take? When can I go home?
When and how will I receive the results of my test?
When should I see you to follow-up?
What other tests or treatments might I need?
What can I expect after a breast MRI?
A breast MRI is usually an outpatient procedure. You can go home and resume your normal activities right away unless your doctor tells you otherwise.
The results of your breast MRI will determine your next steps. Benign results mean there is no cancer and no further treatment may be necessary. If the results indicate a problem, you may need more imaging exams, additional diagnostic tests (such as a breast biopsy), or treatment.