Breast Ultrasound

April 10, 2025

This page was reviewed under our medical and editorial policy by Hannah Chang, M.D., assistant professor, and Susan Yost, Ph.D., staff scientist, Department of Medical Oncology & Therapeutics Research, City of Hope^® Cancer Center Duarte

A breast ultrasound is an imaging test that the care team may use to examine changes in the breast, like breast lumps that might not be visible on a mammogram.

It is not typically used for routine breast cancer screening, but it might be particularly helpful for women with dense breast tissue. This test is often used to get a closer look at suspicious areas on a mammogram, offering more detailed information.

What Is a Breast Ultrasound?

A breast ultrasound is an imaging test that uses sound waves to create detailed pictures of the breast’s internal structures. The test is often used when a physical exam, mammogram or magnetic resonance imaging (breast MRI) finds an abnormality, such as a lump or unusual nipple discharge.

During the procedure, a small device called a transducer is placed on the skin with a gel to help transmit sound waves into the breast. These sound waves bounce back to the transducer, and a computer then converts these echoes into images that the doctor is able to analyze.

One key benefit of a breast ultrasound is its ability to differentiate among different types of abnormalities. For example, it may help determine whether a lump is solid, which could indicate a benign or cancerous tumor, or fluid-filled, such as a benign cyst. This additional information may help health care providers decide the next steps in care.

Breast ultrasounds may also be used as a supplemental screening tool, particularly for women with dense breast tissue, where mammograms might miss certain abnormalities. It is also an option for those who are pregnant or at high risk for breast cancer but are unable to undergo an MRI. In some cases, if the ultrasound detects a suspicious area, it may guide a breast biopsy to gather more information about the tissue.

Can an Ultrasound Detect Breast Cancer?

A breast ultrasound may provide a closer look at changes in the breast, but it does not definitively diagnose cancer. While it may help identify abnormalities that a mammogram might miss, especially in women with dense breast tissue, it does not replace a mammogram for cancer screening.

Ultrasound may detect suspicious areas, but it is unable to confirm whether they are cancerous. If something unusual is found, a biopsy is usually needed to determine whether it is cancer.

Types of Breast Ultrasound

There are two main types of breast ultrasound: handheld and automated breast ultrasound (ABUS). 

Handheld ultrasound: This is the most common type of ultrasound and uses a small, wand-like device called a transducer. A gel is applied to the skin, and the transducer is moved over the area to create images from sound waves. This method may cause some pressure but is not usually painful.

ABUS: This type of ultrasound uses a larger transducer to capture hundreds of images, covering nearly the entire breast. ABUS is sometimes used for women with dense breasts, but a handheld ultrasound might still be needed to examine any suspicious areas further.

Breast Ultrasound Versus Mammogram

A breast ultrasound is not typically used as a replacement for a mammogram but rather as a complementary tool. Mammograms are the primary screening method for breast cancer and are known to reduce deaths through early detection.

However, mammograms do not catch every abnormality, especially in women with dense breast tissue where some areas may be hard to see. A breast ultrasound may provide a clearer view of suspicious areas that a mammogram might miss, offering additional insight when something unusual is detected.

Preparing for an Ultrasound of the Breast

Before a breast ultrasound, patients need to undress from the waist up and are provided a gown to wear. Wearing a two-piece outfit might make this easier.

On the day of the exam, it is important to avoid using lotion, powder or deodorant on the breasts or underarms, as these may interfere with the test. Any jewelry around the neck and chest area should be removed. A mammogram may be required either before or after the ultrasound.

The Breast Ultrasound Procedure

During the procedure, patients lie down face up on an exam table. A sonographer or radiologist applies a water-based gel to the breast, which helps the transducer make secure contact with the skin. The transducer is then moved over the breast area, sending sound waves into the tissue. These waves create a detailed image of the breast, which appears in real time on a computer screen.

Patients may be asked to raise their arms above their head or turn to one side to get clearer images. The procedure is generally painless, though there may be slight pressure if the area being examined is tender.

Once the images are captured, the technologist wipes off the gel, which does not stain or discolor clothing. Patients may be asked to wait while the images are reviewed to ensure everything needed has been captured.

How Long Does a Breast Ultrasound Take?

A breast ultrasound procedure typically takes about 30 minutes to complete.

Overall, the exam is generally quick, painless and well-tolerated by most patients. This makes it a convenient option for evaluating breast changes.

Breast Ultrasound Results

After the ultrasound, a radiologist reviews the images and sends a report to the doctor who requested the exam. This process usually happens quickly, and the doctor then discusses the results with the patient. In some cases, the radiologist may speak with the patient directly after the exam.

Ultrasounds and mammograms utilize the same category system (0 to 6) to report results. Normal results indicate that the breast tissue appears typical, without any abnormalities. If the ultrasound detects something unusual, it may be a noncancerous growth, such as a cyst, fibroadenoma or lipoma. These findings are generally benign and do not require immediate treatment.

If the ultrasound reveals a suspicious area that could be cancerous, the doctor may recommend further testing. This could involve a biopsy, where a small tissue sample is taken for closer examination. The biopsy might be performed surgically, with a needle guided by ultrasound or using a machine similar to that for a mammogram.

The results of a breast ultrasound help guide the next steps in care, whether it is reassurance from normal findings or additional tests to investigate an abnormality.

What Percentage of Breast Ultrasounds Are Cancer?

In most cases, only a small percentage of breast ultrasounds lead to a cancer diagnosis.

According to a 2018 review in the Journal of Breast Imaging, in more than 250,000 breast ultrasound screenings, 7.5% to 10.6% resulted in follow-up testing, but not all of these cases involved cancer. When a biopsy was needed after an ultrasound, about 9% to 11% of those biopsies confirmed cancer. This means that while breast ultrasounds are an important tool for identifying suspicious areas, most findings turn out to be noncancerous.

The care team guides the patient through any necessary steps, if further testing is recommended.

Benefits, Risks and Limitations

Breast ultrasounds offer several benefits, particularly for women with dense breast tissue. This noninvasive imaging method does not use radiation, making it a safe option for examining breast changes. Ultrasound is also appropriate at capturing real-time images of soft tissues, which may help identify abnormalities that might not be visible on a mammogram. It is often used alongside other tests, like mammograms, to provide a more comprehensive view of the breast. However, there are risks and limitations to consider. While ultrasound is a valuable tool, it does not replace mammograms, as it is unable to detect certain early signs of cancer such as calcifications — tiny calcium deposits that may indicate the presence of cancer.

There is also the potential for false positives, where a noncancerous area might appear suspicious, leading to unnecessary follow-up tests or biopsies. On the other hand, false negatives might occur when the ultrasound misses a cancerous lesion.