Reviewed by: Emily F. Conant, MD
Updated October 1, 2010
An ultrasound is an imaging test that uses high frequency sound waves to create pictures of areas inside the body.
During an ultrasound, a technician or doctor will place a probe that makes sound waves onto the breast. The sound waves will go through the breast and be projected onto a screen as an image. The test does not expose you to any radiation.
An ultrasound detects whether a breast abnormality is solid or filled with fluid. A cyst, a benign (not cancerous) mass filled with fluid, will look different on an ultrasound than a solid mass, such as a benign fibroadenoma (a solid, round mass) or a breast cancer.
If the ultrasound shows a solid mass, you may need more tests, such as a needle or core biopsy. The ultrasound cannot detect whether a solid lump is cancer, and it usually cannot see calcifications, tiny specks of calcium about the size of sand grains that are usually harmless but could be a sign of cancer.
If you are under age 30 and you have a lump in your breast, your doctor may recommend an ultrasound first, rather than a mammogram.
Young women often have dense breast tissue that is filled with glands and benign lumps, not cancers. In younger women, ultrasounds are very effective at looking at a specific area of concern and showing the difference between normal dense breast tissue, a benign cyst filled with fluid and solid masses.