What is a breast ultrasound?

Quick Answer
The use of high-frequency sound waves to produce an image of the breast tissue.
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Cancers diagnosed: Breast cancer

Why performed: There are several reasons that breast ultrasounds are performed. After a questionable mammogram, a breast ultrasound may be used to further examine the breast tissue. Some breast conditions may look like a possible cancer on a mammogram but can be identified as benign on ultrasound. For example, breast cysts and some fibroadenomas appear as clear areas on a breast ultrasound, whereas a breast cancer would not. In women under the age of thirty-five, breast ultrasound may be the procedure of choice for screening for breast cancer because younger women have denser breast tissue, which makes it difficult to assess for abnormalities on mammography. Breast ultrasound may also be used to guide a needle biopsy, or needle localization. Ultrasound has proved effective at examining the breasts of women with breast implants. It is often able to illustrate whether the implant has ruptured or not. Mammography does not show fluid leaking from the implant.

Patient preparation: No preparation of the patient is required.

Steps of the procedure: For a breast ultrasound, the patient puts on a hospital gown, which is open in the front, and then lies supine on a table. A pillow is placed under the shoulder of the breast to be scanned. The area to be scanned is uncovered. The patient’s arm is placed up over the head, resting on the examination table. The radiology technician or physician uses a transducer (an instrument to transmit and receive sound waves) to scan the breast tissue. A transducer looks like a small cell phone. A gel is used between the transducer and the patient to enhance the transmission of the sound waves for the scan. The transducer is moved slowly and lightly over the breast tissue. Usually, the breast lesion is viewed in several planes, so that its features can be defined. This is accomplished by changing the angle of the transducer in relation to the breast tissue. The images of the breast are printed for further examination.

After the procedure: No additional patient care is required, so the patient can go home.

Risks: There are no known risks of breast ultrasound for the patient. It appears that sound waves are safe for use on human beings. For the physician, however, there is the risk of making an incorrect diagnosis about the presence of breast cancer. Breast ultrasounds do not differentiate microcalcifications (mineral deposits) in the breast tissue. Microcalcifications that are clustered can be a first sign of a developing breast cancer.

The accuracy of breast ultrasounds can vary with the skill of the technician. Once the ultrasound images have been printed, there is no way to determine the angle of the transducer, or to manipulate the images, as can be done with mammograms. Also, breast ultrasound is not as accurate at assessing the whole breast. It is most effective at assessing a small area of breast tissue.

Results: The images of the breast ultrasound demonstrate the different breast tissues, with the ducts appearing darker than the adipose (fatty) tissue between the ducts. The breast ultrasound is most accurate at identifying breast cysts, which are fluid-filled. If on ultrasound an area of the breast appears particularly dense and opaque, then a breast cancer could be present. Breast ultrasound does not differentiate between benign tumors and malignant (cancerous) tumors or growths. As a result, a breast biopsy is required to identify the type of lesion.


"Breast Ultrasound." American Cancer Society. Amer. Cancer Soc., 17 Sept. 2013. Web. 9 Sept. 2014.

Love, Susan M., and Karen Lindsay. Dr. Susan Love’s Breast Book. Rev. 4th ed. Cambridge: Da Capo, 2005. Print.

Pagana, Kathleen Deska, and Timothy J. Pagana. Mosby’s Manual of Diagnostic and Laboratory Tests. 3rd ed. St. Louis: Elsevier, 2006. Print.

Sencha, Alexander N., Elena V. Evseeva, Mikhail S. Mogutov, and Yury N. Patrunov. Breast Ultrasound. New York: Springer, 2013. Print.

Shetty, Mahesh K. Breast and Gynecological Cancers: An Integrated Approach for Screening and Early Diagnosis in Developing Countries. New York: Springer, 2013. Print.

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