Ultrasound uses high-frequency sound waves that move through your breast to create an image of the breast on a computer screen that is then analyzed by your Providence Saint John’s physician or surgeon. Based on the ultrasound, we may be able to tell whether a lump is a fluid-filled cyst, which is benign, or a solid tumor, which may be malignant. It cannot determine whether a solid lump is cancerous, nor can it detect calcifications.
If you’re under age 30, we may recommend ultrasound before mammography to evaluate a palpable breast lump that can be felt through the skin. Mammograms can be difficult to interpret in young women because their breasts tend to be dense and full of milk glands. On mammograms, this glandular tissue looks dense and white and can hide small cancers. Most breast lumps in young women are benign cysts, or clumps of normal glandular tissue or benign breast lumps such as fibroadenomas.
Surgeons also can use ultrasound to guide biopsy needles precisely to suspicious areas in the breast. Ultrasound may be safely used during pregnancy or in the presence of allergies to contrast dye, because no radiation or contrast dyes are used.
How breast ultrasound works
Breast ultrasound uses a handheld probe called a transducer that sends out ultrasonic sound waves at a frequency too high to be heard. When the transducer is placed on the breast at certain locations and angles, the ultrasonic sound waves move through the skin and other breast tissues. The sound waves bounce off the tissues like an echo and return to the transducer. The transducer picks up the reflected waves, which are then converted into an electronic picture of the breasts.
Prior to the procedure, clear, water-based gel is applied to the skin to allow for smooth movement of the transducer over the skin and to eliminate air between the skin and the transducer.
By using an additional mode of ultrasound technology during an ultrasound procedure, blood flow within the breast can be assessed. An ultrasound transducer capable of assessing blood flow contains a Doppler probe. The Doppler probe within the transducer evaluates the velocity and direction of blood flow in the vessel by making the sound waves audible. The degree of loudness of the audible sound waves indicates the rate of blood flow within a blood vessel. Absence or faintness of these sounds may indicate an obstruction of blood flow.
More recent ultrasound technologies, including three-dimensional (3D) and four-dimensional (4D) ultrasound, tissue harmonic imaging (uses the harmonic signal generated by tissue itself), ultrasound contrast agents, and ultrasound elastography (low-frequency vibration technique used to evaluate movement of breast lesions), also show promise for diagnosing cancerous breast lesions in a noninvasive manner.
Related procedures that may be performed to evaluate breast problems include mammogram, MRI, and breast biopsy.