What is breast MRI?
Magnetic resonance imaging (MRI) is a test that creates detailed images of organs, bones, and other structures inside your body. An MRI uses large magnets and a computer to make the images. It does not use radiation.
An MRI scanner is a large machine with a tunnel. You lie on a table that slides in and out of the tunnel. For a breast MRI, a woman lies face down with her breasts positioned through holes in a table. A breast MRI is often done with contrast dye. It’s injected into a vein in the arm before or during the procedure. The dye can help create clearer images.
Why might I need a breast MRI?
Breast MRI is most often used to look for and assess breast cancer. Some common uses for breast MRI include:
- Examining possible problem spots seen on a mammogram
- Finding early breast cancer in women with dense breast tissue
- Finding early breast cancer in women at high risk
- Checking for cancer in women who have implants or scar tissue
- Finding small tissue changes that a mammogram or ultrasound may miss
- Checking for leakage from a silicone gel breast implant
- Checking the size and precise location of breast cancer lesions
- Helping to determine between lumpectomy or mastectomy
- Finding breast cancer that has spread into the chest wall
- Finding breast cancer that’s returned after lumpectomy
- Assessing the cause of a newly inverted nipple
The American Cancer Society advises breast MRI and a mammogram for some high-risk women at high risk of breast cancer. This includes:
- Women with a BRCA1 or a BRCA2 gene mutation
- Women with a mother, sister, or daughter with a BRCA1 or BRCA2 gene mutation
- Women with a 20 to 25 percent or greater lifetime risk of breast cancer, based on family history and other factors
- Women who have had radiation treatment to the chest between the ages of 10 and 30, such as for treatment of Hodgkin disease
- Women with one of these genetic disorders: Li-Fraumeni syndrome, Cowden syndrome, or Bannayan-Riley-Ruvalcaba syndrome
- Women with a close family member who have one of the above genetic disorders
Your health care provider may have other reasons to advise breast MRI.
What are the risks of a breast MRI?
All procedures have some risks. The risks of this procedure may include:
- Allergic reaction to the contrast dye
- Disruption of any metal in the body
- False positive results that lead to unneeded breast biopsy
- Failure to detect calcium deposits in the breast that may indicate breast cancer
- Discomfort from having to lie still for a long time
- Anxiety from being inside the MRI scanner
In some cases, a person shouldn’t have an MRI. This can include:
- Women with epilepsy
- Women who are pregnant
- Women with pacemakers and other implanted devices
- Women with metal plates, rods, screws, and other surgical devices in the body
Your risks may vary depending on your general health and other factors. Ask your health care provider which risks apply most to you. Talk with him or her about any concerns you have.
How do I get ready for a breast MRI?
Your health care provider will explain the procedure to you. Ask him or her any questions you have. You may be asked to sign a consent form that gives permission to do the procedure. Read the form carefully. Ask questions if anything is not clear.
Tell the health care provider if you:
- Are claustrophobic and may not be able to lie still inside the scanning machine (you may be given a sedative)
- Are pregnant or think you may be pregnant
- Are not able to lie down for 30 to 60 minutes
- Are allergic to or sensitive to medicines, contrast dye, or iodine
Metal in the body can be dangerous during an MRI. Also tell the health care provider if you:
- Have a pacemaker or have had heart valves replaced
- Have any type of implanted pump, such as an insulin pump
- Have a cochlear implant
- Have an older intracranial aneurysm clip
- Have an intrauterine device (IUD)
- Have any surgical metal plates, clips, sutures, pins, screws, rods, staples, or wire mesh in your body
- Have a prosthetic device
- Have a neurostimulator or bone-growth stimulator
- Have any other type of metal implant
- May have metallic fragments anywhere in your body
- Have tattoos or permanent eye liner
- Ever had a bullet wound
- Have ever worked with metal (for example, grinding or welding)
- Have any type of body piercing
- Are wearing a medicine patch
Make sure to:
- Plan to have someone drive you home from the hospital
- Follow any other instructions your health care provider gives you
What happens during a breast MRI?
You may have your procedure as an outpatient. This means you go home the same day. Or it may be done as part of a longer stay in the hospital. The way the procedure is done may vary. It depends on your condition and your health care provider's methods. In most cases, the breast MRI will follow this process:
- You may be asked to remove your clothes. If so, you will be given a hospital gown to wear. You may be asked to remove jewelry or other objects.
- If your procedure will be done with contrast dye, an intravenous (IV) line will be started in your hand or arm.
- You will lie face down on a mobile bed. Your breasts will be positioned through cushioned openings. The bed will then be moved into the magnet of the MRI machine. Pillows or straps may be used to prevent movement during the procedure.
- The technologist will be in a separate room inside the larger MRI room where the scanner controls are located. You’ll be in constant sight of the technologist through a window. Speakers inside the scanner will let the technologist talk with you. You can let the technologist know if you have any problems during the procedure.
- You will be given earplugs or a headset to wear to help block out the noise from the scanner.
- During the scan, you’ll hear a loud clicking noise. You will need to lie still. Any movement can cause problems with the quality of the scan.
- At times, you may be told to hold your breath for a few seconds.
- If contrast dye is used for your procedure, you may feel effects when the dye is injected into the IV line. You may feel a flushing sensation or coldness, a salty or metallic taste in your mouth, a brief headache, itching, nausea or vomiting. These effects usually only last for a few moments.
- Your breasts may feel slightly warm, but this is normal.
- Tell the technologist if you have any breathing trouble, sweating, numbness, or heart palpitations.
- Once the scan has been completed, the table will slide out of the scanner and you will be helped off the table.
- If an IV was inserted for contrast dye, it will be removed.
What happens after a breast MRI?
Get up slowly from the scanner table. This will help to prevent dizziness. If you took sedatives for the procedure, you will need to rest until the sedatives wear off. You will need to have someone drive you home. Your health care provider will talk with you about the results in a follow-up visit.
If contrast dye was used during your procedure, you may be watched for any side effects or reactions to the dye. These may include itching, swelling, rash, or trouble breathing. If you are nursing, do not breastfeed for 36 to 48 hours after a breast MRI with contrast dye.
Call your health care provider if you have any of the below:
- Fever of 100.4°F (38°C) or higher
- Pain, redness or swelling at the IV site
Your health care provider may give you other instructions after the procedure.
Before you agree to the test or the procedure make sure you know:
How much will you have to pay for the test or procedure
- The name of the test or procedure
- The reason you are having the test or procedure
- The risks and benefits of the test or procedure
- When and where you are to have the test or procedure and who will do it
- When and how will you get the results
- Freeborn, Donna, PhD, CNM, FNP
- MMI board-certified, academically affiliated clinician