Breast MRI
Aiding in the Early Detection of Breast Cancer and Evaluation of Breast Diseases
By Carolyn Birnbaum, M.D.

Mammography is considered the standard screening test for breast cancer. However, in recent years, MRI has been incorporated into the armamentarium for evaluation of breast diseases and early detection of breast cancer.

Breast MRI (Magnetic Resonance Imaging) is a breast imaging technique that uses magnetic fields and radio waves to make computer images of the breast, which generates detailed 2-D and 3-D pictures. No radiation or x-rays are used. Contrast material (gadolinium) is administered during the examination.

Breast MRI isn't used routinely for breast cancer screening, but can provide important information in certain specific circumstances. The American Cancer Society provided specific guidelines in 2007 for the use of screening MRI in conjunction with annual mammogram in certain high risk groups. These include the following:

- BRCA1 or BRCA2 (gene) mutation carriers

- First degree relative (parent, sibling, child) with a BRCA1 or BRCA2 mutation even if they have yet to be tested themselves

- Lifetime risk of breast cancer scored at 20% to 25% or greater, based on one of several risk assessment tools that look at family history and other factors

- Radiation to the chest between the ages of 10 and 30

- Specific rare medical syndromes

Specific guidelines for breast MRI screening have not yet been established for situations including: personal history of breast cancer; history of high-risk lesions including atypical ductal hyperplasia, atypical lobular hyperplasia, and lobular carcinoma; and dense breasts.

The role of breast MRI is, however, expanding in the following situations:

- Determining the extent of disease in the involved breast after diagnosis of breast cancer

- Evaluate for tumors in the opposite (contralateral) breast after the cancer has been diagnosed

- Evaluating response to chemotherapy

It should be remembered that breast MRI is used in addition to a mammogram or other breast imaging test - not as a replacement for mammogram.

Although it is a very sensitive test, breast MRI can still miss some breast cancers that a mammogram will detect. In addition, due to the increased sensitivity, MRI can often lead to "false positive" results (a result that indicates cancer when no cancer is present). This can lead to many additional biopsies and increased patient anxiety.

Other limitations include cost, patient claustrophobia, presence of medical hardware or other metallic substances within the body precluding performance of the study, and risk of nephrogenic systems fibrosis from the contrast material in patients with poor kidney function.

It is imperative for patients to talk with their doctors and other health care professionals to determine their risk assessment and decide if breast MRI is useful for them. IMAGE