Breast Ultrasound

Breast ultrasound is often used to examine a breast change that’s seen on a mammogram.

Why is breast ultrasound used?

Ultrasound is useful for looking at some breast changes, such as those that can be felt but not seen on a mammogram or changes in women with dense breast tissue. It also can be used to look at a change that may have been seen on a mammogram. Ultrasound can be used to tell the difference between fluid-filled cysts and solid masses. (If a lump is really a cyst, it’s not cancer.)

Ultrasound can be used to help guide a biopsy needle into an area of change so cells can be taken out and tested for cancer. It can also be used to look for and guide a biopsy needle into swollen lymph nodes under the arm.

Ultrasound is widely available, easy to have done, and costs less than a lot of other options.

How is it done?

Breast ultrasound uses sound waves to make a computer picture of the inside of the breast.

A gel is put on the skin of the breast and an instrument called a transducer is moved across the skin to show the underlying tissue structure. The transducer sends out sound waves and picks up the echoes as they bounce off body tissues. The echoes are made into a black and white image on a computer screen. This test is painless and does not use radiation.

As with any breast imaging, breast ultrasound depends on the level of skill and experience of the doctor interpreting the images. When a handheld transducer is used, ultrasound is also dependent on the skill and experience of the person doing the scan.

Automated ultrasound is an option that uses a much larger transducer to take hundreds of images that cover nearly the entire breast. When automated ultrasound is used, a second handheld ultrasound is often needed to get more pictures of suspicious areas.

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master’s-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Bruening W, Uhl S, Fontanarosa J, Reston J, Treadwell J, Schoelles K. Noninvasive Diagnostic Tests for Breast Abnormalities: Update of a 2006 Review [Internet]. Rockville (MD): Agency for Healthcare Research and Quality (US); 2012 Feb. Available from

Last Medical Review: June 1, 2016 Last Revised: August 18, 2016

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