Beneath the Surface: A Guide to Breast Imaging
Mammography uses very small amounts of x-rays to look inside the breasts. It is considered the “gold standard” of breast imaging for the detection of breast cancer. Mammograms can discover many breast cancers before symptoms, such as a mass, breast pain, skin changes associated with breast cancer, or abnormal nipple discharge, are noted.
Radiologists look at a mammogram for changes in the breast tissue that can be caused by breast cancer, such as abnormal masses and collections of calcification. Some findings seen on mammograms may be linked to noncancerous, or benign, conditions while other findings are linked to cancer. The following mammograms show examples of common benign (non-cancerous) findings and suspicious abnormalities:
Ultrasound uses sound waves to determine differences in breast tissue density. It is complementary to mammography and can sometimes detect problems not found on a mammogram. Ultrasound is most commonly used to determine whether a mass that has been felt or a nodule that has been seen on mammogram is a fluid-filled cyst or a solid growth. Ultrasound also can show blood flow in breast tissue and blood vessels. Many breast surgeons use ultrasound in their offices to complement their physical examination of the breast and axilla (area under the arm). The following ultrasounds show examples of common findings:
Breast MRI is one of the most sensitive ways to detect breast cancer. A breast MRI looks not only at the architecture of the breast but also how a dye flows in and out of breast tissue. The blood flow pattern of dye into a breast cancer is oftentimes different than that seen in normal breast tissue.
While breast MRIs are very sensitive for finding breast cancer, they are not very specific. Because of this, breast MRIs can cause many false alarms, or false positives. False-positive findings, which occur when a noncancerous lesion has the same pattern as a breast cancer, can lead to more biopsies. For this reason, breast MRIs are used primarily to screen patients who have a greater than 20% chance of developing breast cancer in their lifetime, women who have a breast cancer gene (such as BRCA1 or BRCA2), and women who have recently been diagnosed with breast cancer.
Hormonal changes can affect the accuracy of breast cancer detection. So if you are a woman who still has menstrual cycles, it is critical that you schedule your breast MRI at the appropriate time in your cycle. Be sure to ask your physician how to determine the best time for your exam. The following show MRI images of the breast: