Breast MRI

Breast magnetic resonance imaging (MRI) is a tool used to diagnose and stage breast cancer. An MRI machine is a type of medical imaging tool that uses strong, powerful magnets and radio currents to take clear, detailed, three-dimensional images of the breast. In the MRI machine is a special device, known as a dedicated breast coil, that makes it easier to take accurate images.

An MRI is a non-invasive test for patients, which means no tools penetrate the body or the skin. It may be ordered for different reasons, including:

• To screen for breast cancer
• To look for signs of cancer
• To learn more about the size and location of a breast tumor

Beyond breast cancer, a breast MRI may also be used to examine silicone (not saline) breast implants to look for leaks or confirm the source of other concerns.

Why breast MRIs are performed

A breast MRI isn’t a replacement for a mammogram, but it may help doctors see more detailed images of the breast tissue. Patients who meet these criteria may be candidates for a breast MRI:

They are high risk. A breast MRI may be used as a screening tool for patients with a high risk of breast cancer, including those with a personal history of the disease.

They need a small mass diagnosed. An MRI helps determine a more accurate diagnosis, so patients with a small, dense mass in the breast may benefit from an MRI.

They need a tumor sized. For those already diagnosed with breast cancer, an MRI may assist with identifying the size of a tumor, particularly one that may be felt by a doctor but isn’t showing up on an ultrasound or mammogram.

They are undergoing chemotherapy. For breast cancer patients undergoing chemotherapy, an MRI is useful to monitor whether the cancer is responding to treatment and shrinking in size. Because every patient’s diagnosis and treatment plan is different, patients should talk to their medical team to see whether a breast MRI is right for them.

Preparing for a breast MRI

Before an MRI, the medical team will explain what to expect and how to prepare. It’s important that patients follow their pre-imaging instructions. They also will need to let their doctor know whether they’re pregnant, breastfeeding or taking any medications.

MRIs use powerful magnets. Patients should tell their care team if they have metal implants or piercings in their body because some may need to be removed beforehand.

Patients who have any of these metal implants should never enter the MRI area until their team says it’s safe to do so:

• A cochlear hearing implant
• A pacemaker or implanted defibrillator
• Clips used on a brain aneurysm
• Metal coils inserted into blood vessels

MRIs are performed in an enclosed space, so patients should talk to their doctor if they tend to get claustrophobic. Doctors may help ease the patient’s fears by explaining what to expect, and technicians will also be able to talk to the patient during the procedure. Sometimes, patients may be able to choose music to listen to or bring their own music.

What happens during a breast MRI

During a breast MRI, patients will be told what to expect throughout the procedure. Standard breast MRIs usually include these steps:

• The patient lays face down on a padded table made for breast MRIs. The table has special openings for the breasts so they may be examined without being flattened or squeezed.
• The patient and the table are placed into the MRI machine, which may look like a tunnel or tube, though they are more open.
• The MRI technician and the patient may communicate through an intercom. This is how the technician gives instructions throughout the procedure.
• The patient will stay still while two to six images are taken. The MRI machine may make loud tapping sounds when it’s taking pictures. It’s normal for breasts to feel warm during the MRI, and some patients may also feel like they need to urinate.

The MRI process usually takes about 30 minutes but may take longer if the technician needs to retake any images.

Sometimes patients are given a breast MRI with contrast. During an MRI with contrast, a contrast material called gadolinium is injected into the body before the MRI begins. The contrast will show up on the MRI images, helping doctors more easily see abnormal tissue in the breast.

When to expect breast MRI results

Patients typically get breast MRI results back within two weeks, although it may be faster in some cases. Some patients feel nervous or worried when waiting for test results, which is normal.

Breast cancer screening guidelines

Before making the decision to be screened for breast cancer, patients should have a discussion with their doctor about the benefits and risks of screening so they are better equipped to make an informed decision.

The U.S. Preventative Task Force recommends the following breast cancer screening guidelines:

• Women ages 50 to 74 with an average risk of breast cancer should have a mammogram every two years.
• Women ages 40 to 49 should talk to their doctor about when and how often they should have mammograms.

For patients with a high risk of breast cancer, mammograms and breast MRIs may be used for screening. Patients should always talk to their doctor to learn more about screening and whether it’s right for them.