Mammography and Breast MRI – What Patients Should Know

By Mayo Clinic Staff

Mammography has proven to be a very effective in detecting early breast cancer in most patients, and is still the only imaging method that is proven to decrease mortality from breast cancer. However, there are some patients at much higher risk of breast cancer who also have very dense breast tissue on their mammograms. These patients may benefit from additional tests such as breast ultrasound or breast MRI.

Breast MRI is a relatively new, highly specialized test in which a powerful magnet is used to obtain hundreds of images of the breasts, before and after intravenous injection of dye material. A breast MRI takes approximately 45 minutes, during which time patients are asked to remain very still in order for the test to be as accurate as possible.

The advantage of breast MRI is that it is extremely sensitive, which means that it can detect both cancerous and non-cancerous (benign) lesions. However, some cancers and benign findings can appear similar on breast MRI and, as a result, breast MRI can sometimes lead to unnecessary anxiety and biopsies for patients.

The role of breast MRI is still evolving and continues to be studied. When used prudently and appropriately in high-risk patients with dense breasts, breast MRI can be advantageous. However, it cannot detect all cancers. In a recently published study, some cancers were seen only with mammography. Therefore, breast MRI is not considered a substitute for mammography.

The multidisciplinary team of specialists at the Breast Clinic works closely with patients and their families to assure that all treatment options are thoroughly evaluated based on individual needs.