Breast MRI

What is a breast MRI?

Magnetic Resonance Imaging, also called MRI, is a radiology test that uses strong magnets and radiofrequency waves to make a detailed picture of bones, soft tissues (muscles, tendons, etc), organs and other parts of the body. The test does not use any radiation.

An MRI of the breast can give healthcare providers more facts about breast health that cannot be seen on mammogram or ultrasound. MRI does not replace a mammogram. It is used along with a mammogram, as it can miss some cancers that a mammogram would find.

A breast MRI is done with a special MRI machine that has tools designed to make detailed pictures of the breasts. Not all places have this equipment or are trained to read the images made by the test.

What is breast MRI used for?

Breast MRI has many uses, such as:

• Breast cancer screening for women at high risk of breast cancer due to family history or their own past health.
• To check abnormalities seen on mammogram that need further investigating.
• Evaluating a new cancer diagnosis.
• Follow up after treatment for breast cancer.
• Checking breast implants that may have ruptured.

Is there anything special I need to do to prepare for the test?

There is usually no special preparation for a breast MRI. Unless you are told not to, you can eat and drink as you normally would. It is best to leave jewelry, body piercings, hair clips, and other metal at home, as these are not allowed in the MRI room. Let the technician know if you have any metal in your body, such as a defibrillator/pacer, port-a-cath, or other metal implants.

If you are claustrophobic, you may need to take medication to relax before the test. Talk with your healthcare provider if you have any concerns.

How is the test performed?

A breast MRI uses a specially designed table for the exam (called a coil) with holes in it for the breasts. You will lie face down on the table, with your breasts hanging through the holes. This allows the breast tissue to be imaged without being squeezed. The machine may press against the breast some, in order to keep them from moving, but it is not like the compression used during a mammogram. You will need to lie still for the test, so it is important that you get comfortable. The table slides into a tube, with the magnets spinning around you. The machines can be quite noisy and you may be given headphones or earplugs to help block out the noise.

Breast MRI almost always uses a contrast medicine given into a vein (IV) called gadolinium. The one exception to this is when the test is done to look for ruptured implants, as contrast is not needed for that exam. The contrast will be given before the test. The whole test can take 45-60 minutes.

MRI Machine

Lying face down, breasts in cut outs.

What is a “Fast Breast MRI”?

The FAST MRI is sometimes used along with a mammogram for women with dense breast tissue who do not meet the rules for a full breast MRI. It cannot find as many issues as a full breast MRI, but it has been found to be very good at finding invasive breast cancer. The test can be done in as little as 10-15 minutes. Many health plans do not pay for this test. You may have to pay out-of-pocket for the test, which typically costs around $300-400.

Who should have a breast MRI?

Breast MRI is recommended for women at high risk of breast cancer.  The American Cancer Society (ACS) breast cancer screening guidelines suggest yearly screening MRI, along with mammogram, for these women:

• Those with a known BRCA 1 or 2 (genetic) mutation.
• Women who have not had genetic testing, but have a first degree relative with a BRCA mutation (sister, mother, daughter).
• Women with a predicted lifetime risk of 20% to 25% or greater (decided using risk assessment tools - more below).
• Women who received radiation to the chest between the ages of 10 to 30.
• Women with certain genetic syndromes, or a first-degree family member with the syndrome (Cowden, Li-Fraumeni, Bannayan).

What if you don’t meet the criteria above?

There are some women who researchers feel the studies do not give a clear recommendation for. They are at higher risk than the general public but do not fall into the highest risk grouping, making it hard to generalize recommendations for this group. These include women with:

• Predicted lifetime risk of less than 20%, but more than 15%.
• Those with a history of lobular carcinoma in situ (LCIS), atypical lobular or ductal hyperplasia.
• High breast density (dense breast tissue) on mammography.

These women should talk with their healthcare provider about their case and concerns. Perhaps the FAST MRI is an option for them. MRI is not meant to replace mammogram for any woman; it is to be used along with mammogram. Some suggest alternating the tests every six months, while others see a benefit to reading them together.

How do I know my predicted risk?

Many studies sort women based on their predicted lifetime risk of getting breast cancer. There have been tools developed to figure out this risk, and each has its own faults. The tools keep in mind age, family history (both mother and father’s side), age at first menses (period) and age of first pregnancy. Things that lead to being grouped as high risk are:

• Two or more 1st or 2nd degree family members with breast or ovarian cancer.
• Premenopausal breast cancer in a close family member.
• Family history of breast and ovarian cancer.
• One or more family members with 2 cancers.
• Male breast cancer in the family.

Does my family history of cancer mean I am high risk?

It is important to point out that most women with one family member with breast cancer are not at greater risk at all, or only a small increase in risk. While cancers such as ovarian, endometrial (uterus) and colon (bowel) are sometimes linked to breast cancer, most of these cancers are not. It is important for each woman to have a good understanding of their family history and to talk about their risk with their healthcare provider. For many families, talking about illnesses such as cancer has long been forbidden, but these taboos must be broken to best estimate your own risk.

What about cost?

MRI is more costly than mammogram. Coverage by insurance companies will differ and will likely depend on the woman's risk. Be sure to check on your coverage with your insurance company before having a breast MRI.