Breast ultrasound

ALSO KNOWN AS: Sonography, ultrasonography

DEFINITION: A breast ultrasound is the use of high-frequency sound waves to produce an image of the breast tissue. The sound waves range from five to ten megahertz (MHz). They are bounced off of the breast tissue and can distinguish between solid tumors and fluid-filled cysts. The density and elasticity of tissues affect the velocity of the sound waves traveling through them. Tissues that are denser and less elastic slow the sound waves and appear as shaded areas on the screen image. Tissues that are less dense and more elastic do not interfere with the sound waves and appear as clear areas. The sound wave data is interpreted by a computer. An advantage of breast ultrasound is that it does not use radiation.

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 an ultrasound. For example, breast cysts and some fibroadenomas appear as clear areas on a breast ultrasound, whereas breast cancer would not. In women under the age of thirty-five, a 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 ultrasounds 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, on the other hand, does not show fluid leaking from the implant.

In 2012, the U.S. Food and Drug Administration approved a new method of breast ultrasound known as automated breast ultrasound (ABUS). This procedure is helpful for women who have dense breast tissue, as a typical mammogram or breast ultrasound cannot always properly detect abnormalities if the tissue is too thick. In some cases, ABUS are being supplemented for annual mammograms as a potential means of earlier and more accurate detection of abnormalities.

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 for the patient when performing breast ultrasound. 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 sacs. If areas of the breast appears particularly dense and opaque on the ultrasound, then cancer could be present. However, breast ultrasounds cannot differentiate between benign tumors and malignant (cancerous) tumors or growths. As a result, a breast biopsy is required to identify the type of lesion.

However, the advancements of ABUS technologies has allowed for earlier detecting of malignant breast tumors. One study, published in Academic Radiology in 2023, found that the ABUS detected almost thirty-six percent more cancers in women who have dense breast tissue, including some who had negative mammograms.

Bibliography

"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.

“New Study Shows Automated Breast Ultrasound Improves Cancer Detection Rates.” GE HealthCare, 25 October 2023, www.gehealthcare.com/insights/article/new-study-shows-automated-breast-ultrasound-improves-cancer-detection-rates. Accessed 13 June 2024.

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

Ren, Wenhui, et al. “Integration of Handheld Ultrasound or Automated Breast Ultrasound among Women with Negative Mammographic Screening Findings: A Multi-center Population-based Study in China.” Academic Radiology, vol. 30, no. S2, 2023, pp. S114-S126. Academic Radiology, www.academicradiology.org/article/S1076-6332(23)00098-3/fulltext. Accessed 13 June 2024.

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.