Understanding Breast MRI

A breast MRI is more sensitive than a mammogram in detecting breast cancer, but must be used in combination with mammography and/or ultrasound imaging for a complete evaluation. Annual screening mammography is still recommended regardless of whether you have had supplemental imaging with an MRI.

Because a breast MRI is very sensitive, it is more likely to pick up small areas of concern in the breast, some of which may be harmless. As a result, if you have a breast MRI, you may need additional imaging, a biopsy or a short-term follow-up MRI to clarify the findings.

See all screening guidelines for breast cancer.

How Breast MRI Works

MRI technology uses a powerful magnetic field, not radiation, to “see” deep inside the body. The equipment takes 3-D pictures of the breast and its surrounding structures. Breast MRI does require contrast (gadolinium) injection to see abnormalities within the breast. However, patients who have concern about implant rupture may not need contrast. This will be determined based on your reason for the examination.

What to Expect During Breast MRI

Breast MRI is an outpatient procedure that requires no fasting or anesthesia. A standard breast MRI takes about 45 minutes, but we reserve one hour and 15 minutes so that you have time to check in, change and talk with the technologist. Abbreviated breast MRI (abMRI) is a newer screening tool for women with dense breast tissue. AbMRI takes less than 10 minutes and is offered at some Northwestern Medicine facilities.

Preparation instructions may vary by physician and patient, but the following are the basic steps you will experience with a breast MRI.

Before the Procedure

• When you make your appointment, let your scheduler know if you have concerns or anxiety about being in a confined space. The technologist will help you manage those feelings. If you feel that you need a medication to help you through the examination, please contact your referring physician to obtain it.
• When you arrive for your appointment, a specially trained technologist will explain the process and answer your questions.
• You will be asked about your medical history and any recent mammograms you have had. If you have had mammograms at facilities outside of Northwestern Medicine, be sure to bring those images to your appointment.
• Let your technologist know if you have any kidney problems.
• You will need to remove clothes above the waist in addition to any jewelry, dentures, hearing aids or other metal objects, such as belts, that could interfere with the magnetic technology. A hospital gown will be provided.
• An intravenous (IV, in the vein) needle will be inserted into your arm or wrist, and a liquid called gadolinium will be injected through the IV. Often called “contrast,” gadolinium helps highlight any abnormal areas in the imaging. If you are over age 65, you will need blood work before you are given contrast.
• You will lie face down on an examination table with your breasts resting in a plastic, cup-shaped device — they are not compressed as in a mammogram. You will be able to see outside of the MRI machine from where your head is resting, if you choose to. Your arms will be resting next to your head on the exam table.
• The nurse or technologist may give you earplugs or music to reduce the noise coming from the machine.

Movement can affect the quality of images and make it harder to identify suspicious areas. Therefore, the technologist will explain that you need to lie very still and breathe calmly.

During the Procedure

• The examination table will move in and out of a cylinder-shaped machine, which will be taking images of your breasts. The first picture takes 30 seconds to complete. The machine will then continue taking pictures for a total of 45 minutes (or 10 minutes for the abbreviated examination). Your breasts may feel slightly warm, but this is normal.
• When you are inside the cylinder, you’ll hear some loud banging and humming noises.
• The technologist will not be talking with you during the procedure. However, you will be given a device that you can squeeze to notify them if you have a serious need to pause the examination.
• When the examination is completed, you will be asked to remain in position to give the technologist a few minutes to check the images. In rare cases, we may need to take additional images.
• Once all images are completed, your IV line will be removed and your examination will be over.

After the Procedure: Your Results

We understand the anxiety that can occur when you are awaiting the outcome of a medical test. Results will typically be available in one to two business days. Your physician will explain how and when you will receive your results.