What is breast magnetic resonance imaging (MRI)?
Breast MRI is an imaging exam that uses a large magnet, radio waves, and a computer to create detailed images of the breasts. It does not use any radiation but almost always requires the injection of special dye (gadolinium) through an intravenous line (IV). MRI is extremely sensitive for the detection of breast cancer, but can also find many things that may need follow-up and/or biopsy and are not cancer. For this reason, breast MRI is best used as a screening tool (with mammography) in patients who are at higher risk for breast cancer. It is also often used to evaluate patients with certain symptoms or a history of breast cancer.
How do I get ready for the test?
A breast MRI does not require any special preparation. On the day of the test you will be asked to change into a gown and remove all metal jewelry. Patients with defibrillators or certain metallic implants cannot undergo MRI. If you have questions about whether or not you are able to have an MRI for this reason, talk to your doctor. You should also talk to your doctor if you have had a prior allergic reaction to MRI dye (gadolinium). You may need to take medication prior to the exam or avoid breast MRI altogether.
Bring images from any mammograms, breast ultrasound exams, or breast MRIs that you have had at other hospitals or offices on a CD. These will be loaded into our system so the radiologist can compare. This is extremely important as a change from prior images can be a sign of breast cancer.
What will happen during the test?
After you change into a gown, in most cases a nurse will place an IV in your arm. If you are having the breast MRI only to look for problems with silicone breast implants, you will not need an IV. The technologist will bring you into the room with the MRI scanner. She will help you lie face down on the MRI table with your breasts positioned through two openings. Once you are comfortably positioned, the technologist will step out to operate the machine while watching through a window. The table will move into the machine and you will hear noise as the machine collects images. Many patients report a warm sensation or a metallic taste when the dye is injected through the IV. The exam takes about 30 minutes, after which the nurse will remove the IV.
Are there any risks?
The MRI itself has no known risks or side effects. The gadolinium dye that is used for the exam is similarly extremely safe. Gadolinium dyes have been used in the United States for more than 30 years and have been given to millions of patients. A tiny amount of the dye has been found, in some cases, to stay in some parts of the body for months or years. The particular formula of gadolinium dye that we use is one that leaves the least amount of dye behind. Studies have not found any harmful effects from this retention.
After the test
The nurse will remove the IV line and place a small bandage over the site. A radiologist will analyze the MRI images and send a report to your doctor. You should follow up with your doctor to review the results, including whether any additional tests are required. Drink six to eight eight-ounce glasses of water in the 24 hours after the MRI to help remove the gadolinium dye from your body. You can resume your normal activities.