Ultrasound uses high frequency sound waves that are transmitted through the breast tissue from a portable drive called a transducer. These sound waves bounce off tissues of the breast. The "echoes" created as a result then are recorded by a computer that makes an image of the breast tissue and displays it on a monitor. No radiation is used, and very little pressure is required.
Ultrasound scans produce sharp, high-contrast images. Dense breast tissue, ultrasonography can create an image that often allows a doctor to distinguish between a cyst filled with liquid and a solid mass. Mammography does not make this distinction as accurately, even if they are better than ultrasound to detect microcalcifications (which may be an early sign of breast cancer).
Ultrasound imaging does require a qualified operator that can examine suspicious breast by placing transducers in different positions. The operator must decide when to reposition the transducer, or the patient, in order to get the best images.
Often, breast abnormalities that are suspected of being cancer after a mammogram can be identified as benign as a follow-up of ultrasound. Benign breast abnormalities may include cysts and plugged milk ducts. If your doctor sends you to an ultrasound examination, does not always mean that you have cancer--only that there is a need for a clearer picture of your breast.
What can be seen on an ultrasound
Impossible areas deep inside that breastRequires a highly qualified and experienced operatorEquipment may have problemsMay sometimes have difficulty distinguishing between abnormality and surrounding tissueCannot show microcalcifications Advantages of ultrasound image
High-contrast image ImagesCan nonpalpable masses (clots that don't you believe) no compression, pain-freeNo radiationLess expensive CT or MRI Breast More uses for Ultrasound
Ultrasound can also be used to drive a surgeon during a biopsy of the breast so that it can be picked up more accurate sample of tissue. The surgeon also allows an ultrasound to guide the needle during an aspiration of cysts in order to remove the fluid. Lymph nodes may be observed with ultrasound because they form an image feature that distinguishes them from malignancy.
Imaginis.com. Breast Cancer diagnosis. Ultrasound Imaging of the breast. Last update: July 2007. http://www.imaginis.com/breasthealth/Ultrasound.ASP