Breast MRI is a new imaging technique that is used for certain women at very high risk for cancer, whose breast tissue can’t be fully evaluated in the usual ways. In some of these women, clinical exam, self breast exam, mammogram, and ultrasound alone may not give enough useful information. MRI isn’t recommended as a substitute for screening or diagnostic mammography.
For women with diagnosed breast cancer, MRI provides enhanced detection in the breast known to have cancer and the opposite, or “contralateral,” breast. Surgical decisions should not be based solely on MRI findings because not all suspicious lesions on MRI are cancerous. Suspicious lesions should be biopsied before a surgery plan is devised in order to avoid surgical overtreatment. In the rare instances where cancer is found in the lymph nodes but not the breast, an MRI can find the location of cancer in the breast in nearly 60 percent of women.
MRI of the breast used in conjunction with mammography now offers an extremely sensitive image to help resolve the unknown or inconclusive result from a mammogram or ultrasound. This exam does require an injection of a small amount of contrast which enhances the areas within the breast and highlights any areas of concern for abnormality.
Who might benefit from Breast MRI?
- Women with at least two first degree relatives, such as mother and sister with invasive breast cancer, when one of them was found before age 40.
- Women with certain very rare genetic or medical conditions that cause a high risk of cancer.
- Certain women with breast cancer, MRI can help plan surgery when it is not clear that the breast can be saved and full removal (mastectomy) might be needed instead.
- Women with silicone gel implants to detect possible leaking of the implant.
How does the procedure work?
Unlike conventional x-ray examinations and computed tomography (CT) scans, MRI does not depend on ionizing radiation. Instead, while in the magnet, radio waves redirect the axes of spinning protons, which are the nuclei of hydrogen atoms, in a strong magnetic field.
The magnetic field is produced by passing an electric current through wire coils in most MRI units. Other coils, located in the machine and in some cases, placed around the part of the body being imaged, send and receive radio waves, producing signals that are detected by the coils.
A computer then processes the signals and generates a series of images each of which shows a thin slice of the body. The images can then be studied from different angles by the interpreting physician.
Overall, the differentiation of abnormal (diseased) tissue from normal tissues is often better with MRI than with other imaging modalities such as x-ray, CT and ultrasound.
What are some common uses of the procedure?
MRI of the breast is not a replacement for mammography or ultrasound imaging but rather a supplemental tool for detecting and staging breast cancer and other breast abnormalities.
Medical studies are currently being conducted to determine whether MRI and other imaging methods can contribute to the early detection and prevention of deaths from breast cancer.
MR imaging of the breast is performed to:
• assess multiple tumor locations, especially prior to breast conservation surgery.
• identify early breast cancer not detected through other means, especially in women with dense breast tissue and those at high risk for the disease.
• evaluate abnormalities detected by mammography or ultrasound.
• distinguish between scar tissue and recurrent tumors.
• determine whether cancer detected by mammography, ultrasound, or after surgical biopsy has spread further in the breast or into the chest wall.
• assess the effect of chemotherapy.
• provide additional information on a diseased breast to make treatment decisions.
• determine the integrity of breast implants.
Will it hurt?
There is no breast compression for Breast MRI. The MRI scanner does make noise. Patients are given headphones with music to muffle the noise. You could bring your favorite CD to listen to during the procedure.
What position will I be in during the exam?
You will be lying on your stomach. An IV is started prior to the exam for injection of a contrast material.
How long with the exam last?
Between 30-45 minutes