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Breast Ultrasound

(Breast Ultrasonography, Breast Sonogram, Mammographic Ultrasound, Sonomammography, Ultrasound Mammography)

What is breast ultrasound?

Breast ultrasound is a noninvasive diagnostic exam that produces images, which are used to assess breast tissue. Ultrasound may also be used to assess blood flow to areas inside the breasts. The examination is often used along with mammography.

llustration of the anatomy of the female breast, front view
Click Image to Enlarge

Ultrasound uses a transducer that sends out ultrasound waves at a frequency too high to be heard. The ultrasound transducer is placed on the skin, and the ultrasound waves move through the body to the organs and structures within. The sound waves bounce off the organs like an echo and return to the transducer. The transducer processes the reflected waves, which are then converted by a computer into an image of the organs or tissues being examined.

The sound waves travel at different speeds depending on the type of tissue encountered - fastest through bone tissue and slowest through air. The speed at which the sound waves are returned to the transducer, as well as how much of the sound wave returns, is translated by the transducer as different types of tissue.

An ultrasound gel is placed on the transducer and the skin to allow for smooth movement of the transducer over the skin and to eliminate air between the skin and the transducer for the best sound conduction.

Another type of ultrasound is Doppler ultrasound, sometimes called a duplex study, used to show the speed and direction of blood flow. Unlike a standard ultrasound, some sound waves during the Doppler exam are audible.

Ultrasound may be safely used during pregnancy or in the presence of allergies to contrast dye, because no radiation or contrast is used.

More recent ultrasound technologies, such as 3-dimensional (3D) and 4-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), show promise for diagnosing cancerous breast lesions in a noninvasive manner.

Illustration of the anatomy of the female breast, side view
Click Image to Enlarge

Related procedures that may be performed to evaluate breast problems include mammography, breast biopsy, and breast scan.

Anatomy of the breasts

Each breast has 15 to 20 sections, called lobes, which are arranged like the petals of a daisy. Each lobe has many smaller lobules, which end in dozens of tiny bulbs that can produce milk.

The lobes, lobules, and bulbs are all linked by thin tubes called ducts. These ducts lead to the nipple in the center of a dark area of skin called the areola. Fat fills the spaces between lobules and ducts.

There are no muscles in the breast, but muscles lie under each breast and cover the ribs.

Each breast also contains blood vessels and vessels that carry lymph. The lymph vessels lead to small bean-shaped organs called lymph nodes, clusters of which are found under the arm, above the collarbone, and in the chest, as well as in many other parts of the body.

What are the reasons for a breast ultrasound?

A breast ultrasound procedure is commonly performed to determine if an abnormality detected by mammography or a palpable lump is a fluid-filled cyst or a solid tumor (benign or malignant). Breast ultrasound may also be used to identify masses in women whose breast tissue is too dense to be measured accurately by mammography. Breast ultrasound is generally not used as a screening tool for breast cancer detection because it does not always detect some early signs of cancer such as microcalcifications, which are tiny calcium deposits.   

Ultrasound may be used in some women who should avoid radiation, such as pregnant women, women younger than 25 years old, women who are breastfeeding, and women with silicone breast implants. The procedure may also be used to guide interventional procedures such as needle localization during breast biopsies and cyst aspiration (removal of fluid from cyst).

There may be other reasons for your health care provider to recommend breast ultrasound.

What are the risks of a breast ultrasound?

Unlike mammography, breast ultrasound does not use radiation, and therefore poses no risk to pregnant women.

Breast ultrasound may miss small lumps or solid tumors that are commonly detected with mammography.

There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your health care provider prior to the procedure.

Obesity and excessively large breasts may interfere with breast ultrasound.

How do I prepare for a breast ultrasound?

  • Your health care provider will explain the procedure to you and offer you the opportunity to ask any questions that you might have about the procedure.

  • If an invasive procedure such as a needle biopsy is to be done during the breast ultrasound, you may be asked to sign a consent form that gives permission to do the procedure. Read the form carefully and ask questions if something is not clear.

  • No fasting or sedation is required before the procedure.

  • You should not apply any lotions, powder, or other substances to the breasts on the day of the procedure.

  • Dress in clothes that permit access to the area to be tested or that are easily removed.

  • Based on your medical condition, your health care provider may request other specific preparation.

What happens during a breast ultrasound?

Breast ultrasound may be done as an outpatient or as part of your stay in a hospital. Although each facility may have different protocols in place, generally an ultrasound procedure follows this process:

  1. You will be asked to remove any jewelry and clothing from the waist up and will be given a gown to wear.

  2. You will be asked to lie on your back on an examination table and raise your arm above your head on the side of the breast to be examined. Alternatively, you may be positioned on your side.

  3. Ultrasound gel is placed on the area of the body that will undergo the ultrasound examination.

  4. Using a transducer, a device that sends out the ultrasound waves, the ultrasound wave will be sent through the patient's body.

  5. The sound will be reflected off structures inside the body, and the ultrasound machine will analyze the information from the sound waves.

  6. The ultrasound machine will create an image of these structures on a monitor. These images will be stored digitally.

There are no confirmed adverse biological effects on patients or instrument operators caused by exposures to ultrasound at the intensity levels used in diagnostic ultrasound.After the procedure

What happens after a breast ultrasound?

Generally, there is no special care following a breast ultrasound. However, your health care provider may give you additional or alternate instructions after the procedure, depending on your particular situation.

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