Ultrasound uses high-frequency sound waves to create detailed images of the inside of the breast. During a breast ultrasound, a hand-held device, which is called a transducer, is placed directly on the skin to examine any abnormal areas in the breast. The device sends sound waves through the skin into the breast and records the echoes that bounce back from the breast tissue. The signals are sent to a computer which displays them as real time images on a monitor. The images are saved so a radiologist can review them. A breast ultrasound is often used as a follow-up test when there’s an abnormal finding on a screening mammogram, breast MRI or clinical breast exam. This exam is called a targeted breast ultrasound, as it only looks at the abnormal area. Another type of ultrasound called a whole breast ultrasound looks at the entire breast. A whole breast ultrasound doesn’t give as much detail as a mammogram, and it can give both false positive and false negative results. A false positive result indicates a person has breast cancer when they don’t. A false negative result shows a person doesn’t have breast cancer, when in fact, they do. Whole breast ultrasound is not a good breast cancer screening tool by itself. Some studies have shown that combining it with mammography may detect a few more breast cancers than mammography alone in women with dense breasts. This combination of tests can also lead to more false positive results. More research is needed to determine whether it’s helpful when a whole breast ultrasound is combined with mammography or a breast MRI.

Before a breast ultrasound, you’ll be asked to undress from the waist up and put on a gown or robe that opens in the front. You’ll be asked to lie down on the exam table. The ultrasound technician will help you get into the right position for the test. Breast ultrasounds are usually painless since the breast is not compressed during the procedure. An ultrasound technician or radiologist first applies a clear gel to the breast to help the transducer move smoothly across the skin. The device is then pressed against the skin and moved back and forth over the area of concern within the breast. Images are taken throughout the exam and later reviewed by a radiologist. A targeted breast ultrasound can determine whether a lump is a fluid-filled cyst, or a solid mass. However, it can’t determine whether a mass is cancerous or not. An ultrasound may also not be able to detect microcalcifications or abnormalities that are deep within the breast. Follow-up tests and sometimes a biopsy may also be needed to check for breast cancer. Whole breast ultrasound is not part of the National Comprehensive Cancer Network or the American Cancer Society breast cancer screening recommendations for women at average risk, or even for those at higher risk. Talk with your health care provider about whether you need a breast ultrasound. For more information, you can visit the Screening and Early Detection section on komen.org.