Ultrasound scans use high frequency sound waves to capture images and video of the inside of the body. Abdominal ultrasounds to help your doctor see the organs and structures inside the abdomen.

Ultrasounds are safe and painless. They’re also increasingly common. More and more ultrasounds are performed in the United States every year. One study found that their numbers grew by 4 percent every year from 1996 to 2010.

Ultrasound images are captured in real time. They’re able to show the structure and movement of internal organs as well as blood flowing through blood vessels. This test is the most commonly used one to view and examine the fetus in pregnant women, but it has many other clinical uses as well.

Abdominal ultrasounds are used to check the major organs in the abdominal cavity. These organs include the gallbladder, kidneys, liver, pancreas, and spleen.

In fact, if you’re a man between the ages of 65 and 75 and smoke or used to smoke, the Mayo Clinic, recommends you have an abdominal ultrasound to check for an abdominal aortic aneurysm.

If your doctor suspects you have any one of these other conditions, an abdominal ultrasound may be in your near future:

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Abdominal ultrasounds may also be used to help guide your doctor during certain procedures. For instance:

  • During an abdominal biopsy, your doctor may use ultrasound to see where to place the needle to remove a small sample of tissue.
  • Ultrasounds may help your doctor drain fluid from a cyst or abscess.
  • Your doctor may use ultrasound to examine blood flow inside your abdomen.

An abdominal ultrasound has no risks. Unlike X-rays or CT scans, ultrasounds use no radiation, which is why doctors prefer to use them with to check on developing babies in pregnant women.

Fetal ultrasound imaging provides real-time images of the fetus. Though the pictures can be exciting keepsakes for parents-to-be, the U.S. Food and Drug Administration advises parents to have ultrasound scans only when there is a specific medical need. Nothing is gained from exposing the fetus to unnecessary extra ultrasounds, so the FDA advises against these “keepsake videos.”

There’s no evidence that ultrasound imaging and heartbeat monitors cause any harm to fetuses. Yet, doctors still can’t be sure that there aren’t any longer terms risks. Ultrasound can heat tissues in the abdomen slightly. In some cases, it can make very small bubbles in some tissues. The long-term effects of this aren’t known.

Read more: Pregnancy ultrasound »

Ask your doctor if you can continue to drink water and take your medications as you normally would before an ultrasound. Your doctor will usually tell you to fast for 8 to 12 hours before your ultrasound. That’s because undigested food in the stomach and urine in the bladder can block the sound waves, making it difficult for the technician to get a clear picture.

There’s an exception to fasting if you’re having an ultrasound of your gallbladder, liver, pancreas, or spleen. In those cases, you may be instructed to eat a fat-free meal the evening before your test, and start fasting after it.

Before an abdominal ultrasound, you will be asked to change into a hospital gown and remove any jewelry or other objects that might interfere with the scan.

Then you’ll lie down on a table with your abdomen exposed.

An ultrasound technician (sonographer) will put a special lubricating jelly on your abdomen.

The gel prevents air pockets from forming between the skin and the ultrasound transducer, which looks like a microphone.

The transducer sends high frequency sound waves through your body. These waves are too high-pitched for the human ear to hear. But the waves echo as they hit a dense object, such as an organ—or a baby.

If you’re having pain in your abdomen, you may feel slight discomfort during an ultrasound. Make sure to let your technician know right away if the pain becomes severe.

Certain factors or conditions may interfere with the results of an ultrasound, including:

  • severe obesity
  • food inside the stomach
  • barium (a liquid you swallow in some tests that helps your doctor see your stomach and gastrointestinal tract) leftover in the intestines from a recent barium procedure
  • excess intestinal gas

When the scan is done, the technician will clean the gel off your abdomen. The procedure usually lasts less than 30 minutes.

A radiologist will interpret your ultrasound images. Your doctor will discuss the results with you at a follow-up appointment. Your doctor may ask for another follow-up scan or other tests and set up an appointment to check on any issues that were found.