A breast ultrasound uses high frequency sound waves to create a black-and-white image of breast tissues and structures.
In this article, we look at the uses of breast ultrasound, what to expect from the procedure, and how to prepare for it.
Doctors often use ultrasound as an early diagnostic tool to evaluate breast lumps.
Unlike CT scans and X-rays, an ultrasound does not use ionizing radiation. For this reason, doctors often recommend an ultrasound for individuals who are not candidates for radiation-based imaging techniques.
People who should avoid radiation include those who:
- are pregnant or breastfeeding
- are under the age of 25 years
- have breast implants
A doctor may also use an ultrasound to help guide a biopsy needle to collect tissue from a lump for testing. This procedure is called an ultrasound-guided biopsy.
A doctor may schedule a breast ultrasound after discovering a lump in the breast tissue during a routine physical examination or mammogram.
They may also request a breast ultrasound for:
- assessing unusual nipple discharge
- evaluating cases of mastitis, which is the inflammation of the mammary tissues
- monitoring breast implants
- assessing symptoms, such as breast pain, redness, and swelling
- examining skin changes, such as discoloration
- monitoring existing benign breast lumps
- verifying the results of other imaging tests, such as an MRI scan or a mammogram
People should avoid applying any lotions or powders to their skin before the test, as these may decrease the accuracy of ultrasound images.
Having any form of metal on the body can also interfere with the test results, so it is important to avoid wearing jewelry or a watch.
Most breast ultrasounds take place in the radiology department of a hospital, although some might occur in a private or specialist clinic. It is usually a sonographer but sometimes a radiologist who will carry out this test.
Some women who have a breast lump may feel more comfortable with a female sonographer. Those who wish to have a woman perform the test should make this request in advance.
It may also be possible to bring a chaperone, such as a nurse, relative, or friend, who can stay in the room during the test.
Wearing separate items of clothing on the top and bottom instead of a dress or one-piece outfit often makes it easier to avoid removing all clothing. For some people, choosing a button up or zippered shirt might also make the undressing process more comfortable.
Most breast ultrasounds last 15–30 minutes. Ultrasound tests are usually painless unless the lump is tender.
The process begins with the sonographer physically examining the breast. They will then usually ask the person questions about the lump, such as:
- when they noticed it
- whether other symptoms are present
- whether and how it has progressed
After the examination, the sonographer will apply a cool, clear gel to the breast. By limiting air bubbles, this gel enhances the ability of sound waves to move through tissues.
In some cases, the sonographer will place a triangular pillow under the person's shoulder, causing the body to roll to one side. The sonographer may also raise the person's arm over their head. These positions can make it easier for the sound waves to travel and for the tissue to receive them.
The sonographer may dim the lights in the room to make the computer screen and images clearer.
Once the sonographer has evenly spread the gel, they will pass a wand-like device called a transducer over the breast. The transducer sends sound waves through the breast and records their activity.
When a sound wave hits a tissue or structure, it bounces back. The transducer sends information to a computer about how long it takes for the wave to bounce back, as well as its volume, pitch, and frequency. The computer translates this information into an image called a sonogram.
The sonographer will examine all the tissues and structures of the breast and take still images at several different sites and from various angles.
They will usually create multiple still images of the lump and surrounding area. The sonographer may also take short moving videos.
After scanning the breast, they will check the armpit region for swollen or hard lymph glands and nodes.
If a sonographer has any concerns about the image's accuracy, they may ask for a second opinion from a radiologist. Sometimes, the radiologist may need to redo portions of the ultrasound to evaluate the area of concern accurately.
After the test is complete, the sonographer will hand the person a tissue to wipe off the gel and give them privacy to put their clothes back on. Before the person leaves, the sonographer may schedule a follow-up appointment to discuss the results with them.
Waiting for the results of a health test can be stressful and cause anxiety. However, it is important to note that few breast lumps present a significant health risk.
Cysts do not usually require any further treatment unless they are causing pain or are near breast ducts or blood vessels.
Depending on the doctor, practice, or hospital, the results may be ready the same day or a few days later. In most cases, these results will go to a family doctor who will call to discuss them or explain them during an office visit.
Other factors that influence how quickly the results are available include:
- the potential risk of symptoms and the need for prompt treatment
- whether the radiologist needs more information to interpret the results
- whether the doctor needs to compare the results to previous ultrasounds or the results of other imaging tests, such as a CT scan or X-ray
- whether the symptoms could be the result of an underlying condition
- whether the facility is delivering the results by email, fax, phone, or post
Fluid and solid tissue appear differently on the sonogram. If the ultrasound confirms that the lump is a fluid filled cyst, the doctor may discuss the results over the phone.
If the ultrasound detects a solid lump, the results alone will not be enough to confirm or rule out cancer or other conditions. A doctor will often request an MRI and biopsy to evaluate abnormal ultrasound results further.
When interpreting inconclusive or abnormal results, it is helpful to keep in mind that cancer is not the only health condition that causes breast lumps.
Common causes of noncancerous breast lumps include:
- fibrocystic breasts
- intraductal papilloma
- fatty lumps comprising bruised, dead, or injured mammary fat cells
- hyperactive breast glands
- hormone conditions, changes, or therapies
- mastitis or breast infection
- certain medications
If the biopsy leads to a breast cancer diagnosis, the doctor will advise on the next steps.
Will I ever need more than one ultrasound for the doctor to reach a diagnosis?
The steps leading to the diagnosis of a breast lump will differ depending on the circumstances.
Some people may have an ultrasound and receive a clear diagnosis of a fluid filled cyst, for example. It is also possible to have more than one ultrasound before getting a diagnosis.
For instance, a person may have an ultrasound after a suspicious finding on a mammogram and then undergo an ultrasound-guided biopsy of the lump, any suspicious lymph nodes, or both.Yamini Ranchod, PhD, MS Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.