Breast Cancer

Magnetic Resonance Imaging of the Breast

MR scans of the breast, which use a contrast dye and computer-enhanced imaging, provide good detail and are especially good at evaluating dense breast tissue, which is normal in the scan at the top. The bottom scan shows a very early stage of cancer, ductal carcinoma in situ.

Although not a replacement for traditional mammography, magnetic resonance (MR) imaging of the breast is an evolving and growing imaging technique. Breast MR is extremely helpful in evaluating mammogram abnormalities and identifying early breast cancer, especially in women at high risk. High-risk women include those who have had breast cancer or have a mother or sister who has been diagnosed with breast cancer. Breast MR is used most commonly in high-risk women when the findings of a mammogram or ultrasound are inconclusive because of dense breast tissue or there is a suspected abnormality that requires further evaluation.

Breast MR imaging has been in use at Mayo Clinic for several years. More than 700 breast MR scans are performed each year.

MR imaging itself is a painless diagnostic procedure that uses magnets and computers to create pictures or images of areas inside the body. Each image shows a thin, horizontal slice of the breast tissue. A computer compiles the images, which can be studied from many different angles. MR scans produce hundreds of images that the radiologist reads and interprets.

Reading and interpreting breast MRs takes 30 to 45 minutes due to the many images that must be studied. MR scans look for masses like other imaging techniques do, but the technology is sensitive to detecting increased vascularization or new blood vessels that feed tumors. Highlighted by the injection of a special dye, breast tumors enhance or "light up" on MR scans.

If a suspicious area is detected, your doctor may recommend an MR-guided breast biopsy. This type of biopsy may be a preferred alternative to a surgical biopsy. MR-guided biopsy requires only a topical anesthetic, leaves little to no scarring and can be performed in less than an hour.