Breast Ultrasound: Everything You Need to Know

What is a breast ultrasound? What’s the difference between a breast ultrasound vs. mammogram? How long does a breast ultrasound take? BCRF answers common questions about this screening tool

Mammography is the standard screening tool for breast cancer, but there may be instances when a doctor will recommend supplemental screening such as breast ultrasound. Often, an ultrasound is performed if a mammogram shows an abnormality in your breast, such as a lump or distortion, or if you have dense breasts. But doctors also utilize breast ultrasounds in many other situations, such as when performing a breast biopsy or investigating the cause of breast symptoms like pain and nipple discharge.

Read on for more information about the test, its pros and cons, how it compares to mammography, and more.

What is a breast ultrasound?

A breast ultrasound is an imaging technique that uses high-frequency sound waves to capture pictures of the inside of the breast. The sound waves are produced by a handheld probe called a transducer, which detects the waves as they bounce off your breast tissue and create echoes. The transducer, which is connected to a computer, turns the echoes into a picture. Whole breast ultrasound (WBUS) refers to an ultrasound done on the entire breast versus a targeted breast ultrasound on a suspicious spot.

Handheld ultrasound (HHUS) is commonly performed when a mammogram shows something unusual in the breast, such as a lump or mass. Usually, the technician takes images of the suspicious area rather than the whole breast.

Breast ultrasounds are also used to detect breast cancers in women with dense breasts, which contain higher amounts of glandular and fibrous connective tissue (fibroglandular tissue) and lower amounts of fatty breast tissue. Both fibroglandular tissue and abnormal growths appear white on a mammogram, which increases the risk that a malignant tumor or growth is missed by mammography alone. However, they’re different colors on an ultrasound, making it easier for radiologists to detect small cancers that may be hiding in normal breast tissue.

A newer ultrasound device, the automated breast ultrasound system (ABUS), also uses sound waves but a much larger transducer to capture hundreds of images of the whole breast in 3D. The FDA approved it as a secondary screening method for women with dense breasts.

Who should get a breast ultrasound?

Your doctor is more likely to order a breast ultrasound if you:

• Have dense breasts. Women who have category C (heterogeneously dense) or category D (extremely dense) breasts are considered to have dense breasts.
• Have abnormalities on a mammogram. Ultrasounds can help distinguish between solid masses (which might be cancerous) and cysts (which are usually benign).
• Are young and symptomatic. A breast ultrasound is often the first test doctors order if you’re under age 35 and experiencing symptoms such as a lump.
• Are pregnant or breastfeeding. Though the dose of radiation you’re exposed to during a mammogram is low, doctors may first order an ultrasound if you develop breast symptoms while pregnant or nursing to minimize any potential risks to the baby. Ultrasound may also be more likely to detect breast cancer in these circumstances because the breasts sometimes become denser during pregnancy and postpartum.
• Have a higher-than-average risk of breast cancer. Supplemental testing is recommended for high-risk patients, though the preferred test is a breast MRI. But if you’re unable to undergo an MRI, your doctor may recommend a breast ultrasound.
• Have breast implants. Women with implants should have regular mammograms and ultrasounds since both silicone and saline implants can obscure a suspicious lump or mass. A breast ultrasound may also be recommended if you’ve developed complications from your implants or if there are signs of a leak or rupture.
• Have a cyst or fibroadenoma (noncancerous lump) in your breast. Your doctor may monitor these via ultrasound to look for changes in size.
• Experience breast symptoms. Ultrasound can help identify the cause of breast pain, swelling, redness, skin retraction, inversion of the nipple, and nipple discharge.
• Need a breast procedure. Your doctor may use ultrasound to find the ideal placement of a needle or tube to drain fluid from the breast, take a sample of breast tissue (biopsy), or to guide breast surgery.
• Have been diagnosed with breast cancer. Your doctor may order an ultrasound to determine how far cancer has spread in the breast.

Breast ultrasound vs. mammogram: What’s the difference?

Breast ultrasound and mammography both capture images of the inside of the breast, but the technology differs. Ultrasound uses sound waves that reflect off the breast tissue to create detailed images, while a mammogram is an X-ray picture of the breast. Unlike ultrasound, a mammogram does expose your breasts to a small amount of radiation. But for most women, the benefits of regular mammograms outweigh the potential risks of exposure to minimal radiation levels.

Since both types of imaging provide high-quality images of the breast, it might seem like the two are interchangeable. However, mammography is still the most effective tool for breast cancer screening, which is why breast ultrasound is almost always used as a supplement to mammography rather than a replacement.

Mammography remains the gold standard in part because it’s better at detecting stage 0 breast cancer, or ductal carcinoma in situ (DCIS), which develops in the lining of the breast milk ducts. It is the earliest stage of breast cancer and makes up 20-25 percent of all breast cancer diagnoses in the US. Though it isn’t life-threatening, DCIS does increase the risk of developing invasive breast cancer, so it’s critical to detect it before it has a chance to spread into the surrounding breast tissue, lymph nodes, or bloodstream. DCIS can almost always be cured.

Mammography has the advantage in this instance because it’s more likely to show breast microcalcifications than with an ultrasound. These tiny calcium deposits are common and usually harmless, but they can be a sign of DCIS, particularly if they’re present in just one breast rather than both.

What happens during a breast ultrasound?

Wondering what to expect during a breast ultrasound? When you arrive for your appointment, you’ll be asked to undress from the waist up and put on a gown that opens in the front. The technician will have you lie face-up on the exam table and position you with your arm above your head. He or she will apply a clear gel to your breast and the transducer before placing the transducer into position on your skin and taking images. If the technician is using ABUS, they may also use the smaller handheld transducer to take more pictures of suspicious areas of the breast once ABUS is complete.

There’s a chance your technician may step out to talk to your doctor during the test, or the doctor may come into the exam room to look at the images. This may seem worrisome, but it’s not uncommon and doesn’t necessarily mean something is wrong.

How soon you get your results depends on the screening facility’s practices. In some cases, you may get them at the end of your appointment, or you may have to wait several days for the radiologist to read your report and send it to your doctor.

How long does a breast ultrasound take?

A handheld ultrasound usually takes up to 30 minutes to perform a handheld ultrasound, whereas ABUS takes as little as 5 minutes to complete.

A a breast ultrasound painful?

Unlike a mammogram, your breasts do not need to be compressed to get the best images, so breast ultrasounds are typically not painful. At most, you may feel some pressure as the technician moves the transducer over your breast.

Are there breast ultrasound risks?

A breast ultrasound is a safe, noninvasive procedure that doesn’t expose you to radiation or cause side effects. However, it isn’t 100 percent accurate, as there is a chance it may not detect small lumps or solid tumors that show up on mammograms. And it may be less accurate if you’re overweight or have very large breasts.