Magnetic resonance imaging, or MRI, of the breast has been around since the late 1980s but has become more widely used within the past 10 years because of advances in equipment and image quality, and increased experience of interpreting radiologists.
Breast MRI does not replace mammography and breast ultrasound. It plays a complementary role.
MRI might be used with mammography for screening high-risk patients, defined as those with 20 percent or greater lifetime risk of developing breast cancer. These include patients with the known breast-cancer gene mutation BRCA or a history of chest-wall radiation therapy between the ages of 10 and 30. Women who have a mother, sister, daughter or father who have a known BRCA gene mutation also qualify for screening MRI.
Breast MRI can be used to evaluate the extent of disease in patients newly diagnosed with breast cancer. It is also helpful when looking for possible recurrence of breast cancer. Finally, MRI may be used to determine cancer response to chemotherapy before surgery, assess for rupture of a silicon implant or search for underlying cancer in patients with cancer in underarm lymph nodes that has been detected in a biopsy.
Breast MRI is performed with the patient lying face-down on a padded platform. There are two holes within this platform for placement of the breasts. The holes contain coils that optimize the magnetic signals that generate MRI images. There is no radiation in the process.
Gentle compression is applied for breast stabilization. It is crucial for the patient to remain completely still to obtain the best-quality images. The average time to complete the study is 30 minutes.
Breast MRI requires an IV to administer contrast, a solution called gadolinium that becomes bright when exposed to the magnetic field. (Contrast is not used in patients being evaluated for implant rupture.)
Earplugs can help to block the loud sound of the MRI magnet. If a patient is claustrophobic, she can be placed on the table so her head remains outside of the MRI tunnel during imaging.
Breast MRI is a very sensitive tool for imaging the breasts. It is best used in addition to mammography and breast ultrasound for the specific indications mentioned above. Those who have a history of contrast allergy or significant movement disorders, or others with implanted metallic devices, such as pacemakers, are not candidates for breast MRI.