What Is Sonography?

What to expect when undergoing this test

Sonography is a diagnostic medical test that uses high-frequency sound waves—also called ultrasound waves—to bounce off of structures in the body and create an image. The test is often referred to simply as an ultrasound or as a sonogram.

Sonography uses a device called a transducer to send out ultrasound waves and listen for the echo. A computer translates the ultrasound waves into an image. A trained technician can see, measure, and identify structures in the image. A specially trained healthcare provider then reads the images to help diagnose medical conditions.

what to expect during a sonography test
Illustration by Emily Roberts, Verywell

Purpose of Test

A sonogram image can show the sizes and shapes of structures, good and bad, inside the body. The harder and denser the tissue (bone would be the hardest and densest) the more it bounces sound waves back to the transducer and the brighter the resulting image becomes.

Sonography is useful for evaluating the size, shape, and density of tissues to help diagnose certain medical conditions. Traditionally, ultrasound imaging is great for looking into the abdomen without having to cut it open. Abdominal ultrasound, in particular, is often used to diagnose gallbladder disease or gallstones, kidney stones or kidney disease, liver disease, appendicitis, ovarian cysts, ectopic pregnancies, uterine growths or fibroid, and other conditions.

A sonogram is most commonly used is to monitor the development of the uterus and fetus during pregnancy. It can also be used to evaluate glands, breast lumps, joint conditions, bone disease, testicular lumps, or to guide needles during biopsies.

Sonography can also recognize blood or fluid flow. The computer can especially recognize fluid that is flowing toward or away from the transducer and uses color overlays on the image to show direction of flow. Very hard and dense tissues or empty spaces, such as organs filled with gas, do not conduct ultrasound waves and therefore cannot be viewed on a sonogram.

Sonography is often used before moving to imaging technologies that have more potential for complications. Computerized tomography (CT) scanning exposes you to significant levels of radiation. Magnetic resonance imaging (MRI) uses an extremely strong magnet to capture the image. The strength of an MRI magnet can limit its use in patients with metal in their bodies (braces, for example).

Risks and Contraindications

A sonogram is a noninvasive imaging test and has no known complications. Ultrasound waves are thought to be harmless and the test is usually performed externally on the surface of the skin. Sonography has no known risks or complications when used externally on the surface of the skin.

While the energy of the ultrasound waves could potentially irritate or disrupt tissues with prolonged exposure, the computer modulates the power of the sound and a trained technician uses techniques to minimize exposure times and angles. So, sonography is the safest of the imaging tests.

Before the Test

Healthcare providers order sonography often as a first-line test, usually together with blood tests. Make sure you ask the healthcare provider if there are any special instructions before the sonogram.

In an emergency setting, sonography will typically be performed right away. For a test on a future date, find out if you should, or should not, eat or drink anything before the test. For example, healthcare providers will often ask you to fast (not eat or drink) for six hours before an abdominal ultrasound to look at the gallbladder, but tell you to drink several glasses of water and not urinate before a sonogram of the bladder.


A sonogram usually doesn’t take longer than 30 minutes. In most cases, it’s important to arrive about 15 minutes before the test for the intake process.

If the test requires that you drink fluids to have a full bladder, you might need to drink water before the test if the bladder is not full enough. This might happen after the technician tries the test first.

Once the technician acquires all of the pictures, he or she will check with the radiologist (healthcare provider trained to read images) to make sure no other views are required.

Most of the time, the technician is not able to give you any results. Once the radiologist interprets the images from the sonogram, the report will be made available to your healthcare provider.


Sonography is done at most imaging centers, hospitals, and some obstetrics offices. The sonography machine looks a bit like a computer with a microphone attached, almost like a Karaoke machine.

Usually, the sonography machine is rolled right up to the bedside.

What to Wear

You should wear something easy to remove. In most cases, you will only have to expose the skin that the technician is going to need access to. An abdominal ultrasound, for example, can be done wearing pants and a shirt. You will just have to pull the shirt up to expose the abdomen.

In the case of a transvaginal sonogram, you will have to undress below the waste, including removing the underwear.

Food and Drink

As noted above, the reason for the sonography will determine whether you needs to fast, drink fluids, or neither.

Cost and Health Insurance

Sonography is a relatively inexpensive imaging test. It is covered by most insurances and might require pre-authorization depending on the reason the healthcare provider ordered the sonogram.

A 3D or 4D sonogram is an elective test that some parents will get during pregnancy. The 3D image shows a 3-dimensional rendering of the baby, while 4D refers to an animated video rendering of the baby in utero captured over time. These are known as entertainment tests and are not covered by most health insurances.

During the Test

Here's what you can expect before, during, and after a sonogram.


Plan to arrive slightly earlier than your appointment so that you can check in and fill out any necessary paperwork. If you were asked to follow specific food and drink instructions, you will be asked to confirm that you did.

Throughout the Test

A sonogram is conducted by a single technician right at the bedside. The entire sonogram will likely take less than 30 minutes.

The technician will ask you to undress enough to expose the area where the test will be performed and to lie down on the bed.

The technician will coat the transducer with conductive gel, which feels like lubricant jelly. If possible, depending on the tools and supplies available, the gel will be warm. Then the technician will slide the transducer over the skin, sometimes with firm pressure. Occasionally the pressure could cause some mild discomfort.

Using the transducer to point to areas of interest, the technician will use the computer to capture images and might use a mouse to drag lines across the screen. The lines help measure size, like a virtual yardstick.


When the sonogram is over, the technician will usually provide a towel to wipe off the conductive gel. Once the technician confirms that all the necessary images have been captured, you will be free to get dressed. There are no special instructions or side effects to manage.

Interpreting the Results

It only takes the radiologist a few minutes to interpret most sonography results. The results will describe what is on the images and what those findings might suggest. This can mean various things depending on the area of the body tested.

Typically, the results will be provided back to the healthcare provider to share with you. If you don't hear back, be sure to follow up. If needed, you can also request a copy of the radiologist's report and even a disc containing the original images.

A Word From Verywell

Sonography is one of the most noninvasive diagnostic medical tests available. It is a safe option for patients who need to know what is going on inside their bodies. If images are necessary, ask your healthcare provider if ultrasound in an option.

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2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Tomizawa M, Shinozaki F, Hasegawa R, et al. Abdominal ultrasonography for patients with abdominal pain as a first-line diagnostic imaging modality. Exp Ther Med. 2017;13(5):1932-1936. doi:10.3892/etm.2017.4209

  2. U.S. Food and Drug Administration. Center for Devices and Radiological Health. Ultrasound Imaging.

Additional Reading