Ultrasound

Ultrasound (also called sonography or ultrasonography) is a noninvasive imaging test that lets healthcare providers “see” inside your body. Ultrasound uses high-frequency sound waves to create real-time pictures or video of internal organs or other soft tissues. An ultrasound picture is called a sonogram. A doctor or a healthcare provider called an ultrasound technologist or sonographer performs ultrasounds.

Healthcare providers use ultrasound to look at different parts of your body for many reasons.

The three main categories of ultrasound are:

• Pregnancy ultrasound: Providers use prenatal ultrasound to confirm you’re pregnant, estimate your due date and check fetal growth.
• Diagnostic ultrasound: Providers use diagnostic ultrasounds to view internal organs and tissues to see if something is wrong or not working properly. Examples include an abdominal ultrasound, breast ultrasound and transrectal ultrasound.
• Ultrasound guidance for procedures: Providers sometimes use ultrasound to help guide needles, catheters or other instruments during a surgery or procedure. For example, a biopsy or nerve block can require ultrasound guidance.

3D and 4D ultrasounds

Most ultrasound images are 2D (two-dimensional). This is the most common type of ultrasound imaging healthcare providers use. It produces a flat image of your organs and internal structures.

Three-dimensional (3D) ultrasound is another type of ultrasound. This type produces more detailed images because it shows the depth and angles that a 2D ultrasound can’t produce.

Four-dimensional (4D) ultrasound is 3D ultrasound in motion. You can think of it as a “live” 3D image.

How does an ultrasound work?

During an ultrasound, a healthcare provider passes a device called a transducer or probe over an area of your body or inside a body opening. The provider applies a thin layer of gel to your skin so that the ultrasound waves transmit from the transducer through the gel and into your body.

The probe converts electrical current into high-frequency sound waves and sends the waves into your body’s tissue. You can’t hear the sound waves.

Sound waves bounce off structures inside your body and back to the probe, which converts the waves into electrical signals. A computer then converts the pattern of electrical signals into real-time images or videos, which are displayed on a computer screen nearby.

How do I prepare?

The preparations will depend on the type of ultrasound you’re having. For example, you may need to have a full bladder for pelvic ultrasounds or an empty stomach for ultrasounds involving your digestive tract. Your provider may ask you to remove jewelry or clothing depending on the area they’re examining.

Some types of ultrasounds require no preparation at all. Your provider will let you know whether you need to do anything special to prepare for your ultrasound.

What happens during an ultrasound?

Preparation for an ultrasound varies depending on the body part you’ll have scanned. Your provider may ask you to remove certain pieces of clothing or change into a hospital gown.

Ultrasounds that involve applying the transducer over your skin (not in your body) follow these general steps:

1. You’ll lie on your side or back on a comfortable table.
2. The ultrasound technologist will apply a small amount of water-soluble gel onto your skin over the area to be examined. This gel doesn’t harm your skin or stain your clothes.
3. The technologist will glide a handheld transducer or probe over the gel to get images inside your body.
4. The technologist may ask you to be very still or to hold your breath for a few seconds to create clearer pictures.
5. Once the technologist has gotten enough images, they’ll wipe off any remaining gel from your skin, and you’ll be done.

If the transducer is going inside your vagina or rectum, it follows the same general steps above, but with one exception. Before the exam, your provider will put a sterile, lubricated cover on the transducer. This is so the transducer goes in more easily.

Ultrasounds performed over your skin are generally not painful. You won’t feel the sound waves that ultrasound uses. Ultrasounds that go inside body cavities may be uncomfortable, but they shouldn’t hurt.

An ultrasound test usually takes 30 minutes to an hour. If you have any questions about your specific type of ultrasound, ask your healthcare provider.

Are ultrasounds safe?

Yes, research has largely shown ultrasound technology to be safe with no harmful side effects. Ultrasound doesn’t use radiation, unlike some other medical imaging tests, such as X-rays and CT scans.

Still, all ultrasounds should be done by a professional who has training in using this technology safely.

When should I know the results?

The time it takes to get your results depends on the type of ultrasound you get. You may get results quickly, or it may take several days for a radiologist to analyze the images. Once they do, they’ll send a report to the provider who requested the ultrasound. Your provider will then share the results with you.

An ultrasound report usually contains information about normal or abnormal findings, which are separated by the organ or structure being looked at:

• If your ultrasound is normal, it may say “no evidence” of a specific condition or that your organ is of “normal size.” It may also say conditions “weren’t detected.”
• If your ultrasound is abnormal, your provider may note the size of a mass or cyst, or use words like “evidence of” or “findings of” to describe what they see on your organs or tissues.

You should always talk to your provider if you’re unsure about what your ultrasound report says.

What conditions can ultrasound detect?

Ultrasound can help providers diagnose a wide range of medical issues, including:

• Abdominal aortic aneurysm
• Abnormal growths, such as tumors or cancer
• Blood clots
• Cholecystitis
• Ectopic pregnancy
• Enlarged spleen
• Gallstones
• Kidney or bladder stones
• Varicocele

What questions should I ask my healthcare provider?

If you need an ultrasound, you may want to ask your provider the following questions:

• What type of ultrasound do I need?
• What should I do to prepare for my ultrasound?
• Do I need any other tests?
• When should I expect to get test results?