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Breast ultrasound uses sound waves and their echoes to make computer pictures of the inside of the breast. It can show certain breast changes, like fluid-filled cysts, that can be harder to see on mammograms.
Ultrasound is not typically used as a routine screening test for breast cancer. But it can be useful for looking at some breast changes, such as lumps (especially those that can be felt but not seen on a mammogram). Ultrasound can be especially helpful in women with dense breast tissue, which can make it hard to see abnormal areas on mammograms. It also can be used to get a better look at a suspicious area that was seen on a mammogram.
Ultrasound is useful because it can often tell the difference between fluid-filled masses like cysts (which are very unlikely to be cancer) and solid masses (which might need further testing to be sure they're not cancer).
Ultrasound can also be used to help guide a biopsy needle into an area of the breast so that cells can be taken out and tested for cancer. This can also be done in swollen lymph nodes under the arm.
Ultrasound is widely available and is fairly easy to have done, and it does not expose a person to radiation. It also tends to cost less than other testing options.
Most often, ultrasound is done using a handheld, wand-like instrument called a transducer. First a gel is put on the skin and/or the transducer, and then the transducer is moved around over the skin. It sends out sound waves and picks up the echoes as they bounce off body tissues deeper under the skin. These echoes are made into a picture on a computer screen. You might feel some pressure as the transducer is moved around on your skin, but it should not be painful.
Automated breast ultrasound (ABUS) is an option at some imaging centers. This technique uses a much larger transducer to take hundreds of images that cover nearly the entire breast. ABUS might sometimes be done as an added screening exam for women who have dense breasts. It might also be used in women who have abnormal findings on other imaging tests or who have breast symptoms. When ABUS is done, a second handheld ultrasound is often needed to get more pictures of any suspicious areas.
Doctors use the same standard system to describe results of mammograms, breast ultrasound, and breast MRI. This system (called the Breast Imaging Reporting and Data System or BI-RADS) sorts the results into categories numbered 0 through 6.
By sorting the results into these categories, doctors can describe what they find on an ultrasound using the same words and terms. This makes communicating about these test results and following up after the tests much easier.
For more details on the BI-RADS categories, see Understanding Your Mammogram Report. While the categories are the same for each of these imaging tests, the recommended next steps after these tests might be different.
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.
American College of Radiology. ACR BI-RADS ATLAS – Breast Ultrasound. Reporting System. 2013. Accessed at https://www.acr.org/-/media/ACR/Files/RADS/BI-RADS/US-Reporting.pdf on November 29, 2021.
Esserman LJ, Joe BN. Diagnostic evaluation of women with suspected breast cancer. UpToDate. 2021. Accessed at https://www.uptodate.com/contents/diagnostic-evaluation-of-women-with-suspected-breast-cancer on October 11, 2021.
National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology. Breast Cancer Screening and Diagnosis. Version 1.2021. Accessed at https://www.nccn.org/professionals/physician_gls/pdf/breast-screening.pdf on October 11, 2021.
Rella R, Belli P, Giuliani M, et al. Automated breast ultrasonography (ABUS) in the screening and diagnostic setting: Indications and practical use. Acad Radiol. 2018;25(11):1457-1470.
Sedgwick EL. Chapter 12: Imaging Analysis: Ultrasonography. In: Harris JR, Lippman ME, Morrow M, Osborne CK, eds. Diseases of the Breast. 5th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2014.
Venkataraman S, Slanetz PJ, Lee CI. Breast imaging for cancer screening: Mammography and ultrasonography.
UpToDate. 2021. Accessed at https://www.uptodate.com/contents/breast-imaging-for-cancer-screening-mammography-and-ultrasonography on October 11, 2021.
Last Revised: January 14, 2022
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