Breast Ultrasound and Preparation

What Is Ultrasound Imaging of the Breast?

Breast ultrasound is also called ultrasound scanning or sonography. It exposes part of the body to high-frequency sound waves to produce pictures of the inside of the breast. Unlike x-rays, it does not use ionizing radiation.

Common Uses

• Determining the nature of a breast abnormality. Doctors mainly use breast ultrasound to help diagnose an abnormality found on a physical exam, such as a lump, or bloody or spontaneous clear nipple discharge. They also use it to characterize something a mammogram or breast MRI has already shown. Ultrasound can show whether an abnormality is solid (a non-cancerous lump or a cancerous tumor), fluid-filled (such as a benign cyst), or both. It can also reveal additional features of the area, and Doppler ultrasound can assess blood supply to a lesion.
• Supplemental breast cancer screening. Mammography is the only screening tool shown to reduce breast cancer deaths through early detection. But it doesn’t catch every cancer — some abnormalities are hard to see on a mammogram, especially in dense breasts (more ducts, glands, and fibrous tissue, less fat). Ultrasound and MRI can supplement mammography by finding small cancers a mammogram might miss. MRI is more sensitive than ultrasound for this, but not every woman can access it. If you have a screening MRI, you usually won’t need a screening ultrasound too. Your doctor may still use ultrasound to characterize or biopsy something the MRI finds. Ultrasound screening does turn up more findings that call for biopsy than mammography or MRI. Most of these findings turn out not to be cancer, which limits its use as a stand-alone screening tool.

How Should I Prepare?

You’ll undress from the waist up and wear a gown. Tell the radiologist and sonographer about any palpable abnormality you or your doctor has found. Also mention any focal pain or tenderness and its location. Your family history of breast cancer and any previous breast surgery or procedures matter too. It helps to compare against prior mammograms or ultrasounds, so please bring copies of past reports or studies to your appointment.

How Does the Procedure Work?

Ultrasound works on the same principle as the sonar that bats, ships, fishermen, and weather services use. A sound wave strikes an object and echoes back. Measuring that echo reveals the object’s distance, size, shape, and consistency (solid, fluid-filled, or both). In medicine, this lets us detect changes in organs, tissues, and vessels, or spot abnormal masses such as tumors.

A transducer both sends the sound waves and records the echoes. When the technologist presses it against your skin, it sends small pulses of inaudible, high-frequency sound into the body. As these bounce off internal organs, fluids, and tissue, the transducer’s sensitive microphone records tiny shifts in pitch and direction. A computer measures these instantly and builds a real-time picture on the monitor. The technologist typically captures one or more frames as still images.

What Will I Experience During and After the Procedure?

Most ultrasound exams are painless, fast, and easy. Once you’re positioned on the table, the technologist applies warm, water-based gel to your skin. They press the transducer against your body and move it over the area of interest until they capture the needed images. This usually causes no discomfort, though scanning over a tender area may cause some pressure or minor pain. You may need to change position during the exam. Once imaging is complete, the technologist wipes off the gel and you can resume normal activities right away.

Who Interprets the Results, and How Do I Get Them?

A radiologist is a physician trained to supervise and interpret radiology exams. They review the images and send a signed report to your primary care physician or the doctor who referred you. That doctor will share the results with you.

You may sometimes need a follow-up exam. Your doctor will explain why: to clarify a suspicious finding with additional views or a different technique, to track a known abnormality over time, or to check whether treatment is working.

What Are the Limitations of Breast Ultrasound?

• Ultrasound is one tool among several — it doesn’t replace routine screening mammography or a careful clinical breast exam.
• Many cancers aren’t visible on ultrasound.
• Your doctor may still recommend a biopsy to determine whether a suspicious finding is cancer.
• Most suspicious ultrasound findings that lead to biopsy turn out not to be cancer.
• Ultrasound can’t show many calcifications that are visible on mammography. Some early cancers show up only as calcifications on a mammogram.

What Does the Equipment Look Like?

An ultrasound scanner has a console (computer and electronics), a video display, and a transducer. The transducer is a small hand-held device resembling a microphone, attached to the scanner by a cord. It sends inaudible, high-frequency sound into the body and listens for the returning echoes — the same principle sonar-equipped boats and submarines use.

The image appears immediately on the display. The strength, frequency, and travel time of the sound signal as it returns from the tissue determine what that image looks like, along with the type of tissue it travels through.

How Is the Procedure Performed?

You’ll lie on your back on the exam table and may need to raise your arm above your head. The technologist applies a clear, water-based gel to help the transducer make secure contact with the skin and remove air pockets that would otherwise block the sound waves. They then press the transducer against the skin, sweeping over the area of interest. They may also angle the beam from further away to get a better look at an area of concern.

Once the exam is complete, you may need to dress and wait while the technologist reviews the images. The exam usually takes less than 30 minutes.

Benefits vs. Risks

Benefits

• Most scanning is non-invasive (no needles or injections) and usually painless.
• Widely available, easy to use, and less expensive than other imaging methods.
• Uses no ionizing radiation.
• Gives a clear picture of soft tissue that doesn’t show up well on x-rays.
• Can help detect lesions in women with dense breasts, and characterize a lesion that mammography alone can’t interpret.
• Helps physicians confirm that many areas of clinical concern are just normal tissue (like fat lobules) or benign cysts. For most women 30 and older, we use a mammogram together with ultrasound. For women under 30, ultrasound alone is often enough to decide whether a biopsy is needed.

Risks

• Standard diagnostic ultrasound has no known harmful effects on humans.
• A breast ultrasound may lead to further procedures, such as a follow-up scan, aspiration, or biopsy. Most areas flagged only on ultrasound turn out to be non-cancerous.

Please let us know before your exam begins if you may be pregnant.

Ready to book your breast ultrasound? Visit our Ultrasound service page for booking details, or book an appointment directly.