How does a breast ultrasound help diagnose breast cancer?

This technology uses high-frequency sound waves to produce precise images of the breast tissues. It allows doctors to detect the slightest abnormalities in dense breasts and helps them determine whether a lump is a cyst (sac containing fluid) or a solid mass. It can also be used to precisely locate the position of a tumor in order to guide your doctor during a biopsy or aspiration procedure. For example, in some cases, surgical oncologists will use an intraoperative ultrasound during a lumpectomy to mark out the boundaries of the tumor prior to its removal.
Ultrasound is most commonly used when an abnormality is seen on mammogram or when a breast lump is felt, and can help determine if the mass is fluid filled (a cyst) or solid, and if it is suspicious in appearance. Ultrasound is also being used more often in addition to mammography in women with normal mammograms, especially those with dense breast tissue. Breast tissue that is dense is harder to image on mammogram, and ultrasound is proving to be very to detect cancers in dense breast tissue that might be missed by mammogram alone.
To help diagnose breast cancer, a breast ultrasound:
  • Is the most common way to further test the breast after a mammogram.
  • Can tell if a cyst is solid or is filled with fluid.
  • Is used to further examine lumps, pain, nipple discharge, and large lymph nodes.
  • Is used for pregnant or young women with symptoms who cannot get an x-ray.
Ultrasound, also known as sonography, uses sound waves to outline a part of the body. For this test, a small, microphone-like instrument called a transducer is placed on the skin (which is often first lubricated with ultrasound gel). It emits sound waves and picks up the echoes as they bounce off body tissues. The echoes are converted by a computer into a black and white image that is displayed on a computer screen. This test is painless and does not expose you to radiation.
Ultrasound has become a valuable tool to use along with mammography because it is widely available and less expensive than other options, such as MRI. The use of ultrasound instead of mammograms for breast cancer screening is not recommended. Usually, breast ultrasound is used to target a specific area of concern found on the mammogram. Ultrasound helps distinguish between cysts (fluid-filled sacs) and solid masses and sometimes can help tell the difference between benign and cancerous tumors.
Ultrasound may be most helpful in women with very dense breasts. Clinical trials are now looking at the benefits and risks of adding breast ultrasound to screening mammograms in women with dense breasts and a higher risk of breast cancer.