Breast Magnetic Resonance Imaging (MRI)

What is breast magnetic resonance imaging (MRI)?

Breast magnetic resonance imaging (MRI) is a non-invasive imaging technique that uses magnetic field and radio waves to create detailed images of the breast.

MRI can be used as a screening tool in high-risk patients. Current guidelines include screening MRI with mammography for certain groups of women who are considered to be of higher risk (compared to the general population):

Women with BRCA1 or BRCA2 mutation
Women with a first-degree relative (mother, sister, and/or daughter) with a BRCA1 or BRCA2 mutation
Women with a 20% to 25% or greater lifetime risk of breast cancer, based on 1 of several accepted risk assessment tools that look at 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 lymphoma
Women with multiple fillers in the breast which makes it difficult for standard mammograms and ultrasound to detect cancers

Why do you need breast MRI?

A breast MRI can also be used as a diagnostic tool to:

Further work up of abnormalities detected on mammogram and/or ultrasound
Determine extent of cancer after diagnosis of breast cancer
Evaluate response of chemotherapy for some breast cancers before definitive surgery
Evaluate integrity of breast implants if there is suspicion of leakage

You should discuss with your doctor as he/she will recommend the best imaging option based on your condition.

What are the risks of breast MRI?

A breast MRI is a safe and painless procedure. However, there are some associated risks such as:

Allergic reaction to the contrast medium. Allergic reaction to MRI contrast is extremely rare. Mild allergic reactions may include nausea, headaches and dizziness. Severe, life-threatening reactions are exceedingly rare.
False positive result. The MRI scan might identify normal breast tissues as suspicious areas. You may be required to undergo further tests such as ultrasound or breast biopsy, and this may cause unnecessary anxiety and stress.

How do you prepare for breast MRI?

Inform your doctor if:

You have any medical devices or implants in your body. Examples of these are cardiac pacemaker or defibrillator, implantable pump, electronic stimulator, clips, staples, screws, rods and plates. Bring along the device/implant information card (if any) during your scan appointment.
You are pregnant or suspected to be pregnant.
You have claustrophobia or fear of confined spaces. Your MRI scan may be performed under sedation. Please highlight this when making an appointment with us. You will need to fast if sedation is required.

In most cases, surgical staples, plates and screws pose no risks during MRI if they have been in place for more than 4 weeks.

What can you expect in breast MRI?

A breast MRI is typically an outpatient procedure, so you can go about your day after the scan is completed.

Estimated duration

A breast MRI scan takes around 30 – 45 minutes.

Before the MRI scan

You will need to change into a gown and remove all loose items such as jewellery, watch, keys, coins, smartphone, wallet and cards.
You will need to fill a pre-MRI questionnaire to provide information on your medical history. Indicate if you have any medical device/implant or aesthetic procedures performed, such as permanent eyeliner, magnetic eyelashes and skin tattoo. Also indicate if there is foreign body, such as bullet or metal shrapnel, in your body.
The radiographer will go through the questionnaire and explain how the scan will be performed.
Breast MRI is usually performed with contrast injection. A contrast medium acts like a dye when it is injected into your blood vessel. It helps to delineate the body organs and soft tissues for better visualisation. A nurse will set an intravenous line on your arm for contrast injection.

During the MRI scan

You will lie face down on the scan table with your breasts positioned in a special coil.
Headphone or ear plugs will be provided, and a call bell/button will also be provided if you need to call the radiographer during the scan.
The scan table will move into the magnet bore or tunnel. There will be intermittent knocking and humming sounds throughout the scan. This is caused by the changes in gradient fields in the magnet.
It is important to remain still during the scan. Any body movement will cause blurry images and the scan will have to be repeated.
You should not feel any discomfort during the scan. However, some patients may feel warm after some time in the magnet. This is normal but if it bothers you, you can press the call bell and inform the radiographer.
The first part of the scan will be done without contrast injection while the second part will begin after contrast has been injected into your body. Allergic reaction to MRI contrast is extremely rare. Should you feel any discomfort after the contrast injection, inform the nurse or radiographer immediately.

After the MRI scan

You will be brought out from the scan room and the nurse will remove the intravenous line from your arm. Do let the nurse know if you feel pain or discomfort after the scan.

If you had your MRI scan under sedation, the nurse will monitor you for a short period until you are fit to be discharged.

You will receive your MRI results within 2 working days after the scan. Your doctor will review the results and discuss with you if further investigations are needed.