Abdominal Ultrasound

Why It Is Done

Abdominal ultrasound is done to:

• Find the cause of belly pain.
• Find, measure, or monitor an aneurysm in the aorta. An aneurysm may cause a large, pulsing lump in the belly.
• Check the size, shape, and position of the liver. It may also check for problems of the liver. These include jaundice, cirrhosis, or fatty liver. This test may be done to follow up after liver function tests.
• Look for gallstones, inflammation of the gallbladder, or blocked bile ducts.
• Learn the size of an enlarged spleen and look for damage or disease.
• Find problems with the pancreas, such as a tumor.
• Look for blocked urine flow in a kidney. If needed, a kidney ultrasound can find out the size of the kidneys, detect a mass, or detect fluid surrounding the kidneys. It can also look for causes of bladder infections that won't go away. Or it can check how the kidneys are doing after a transplant.
• Find out if a mass in a belly organ is a solid tumor or a fluid-filled cyst.
• Guide the placement of a needle or other tool during a biopsy.
• Look for fluid buildup in the belly cavity. This problem is called ascites. An ultrasound also may be done to guide the needle during a paracentesis. This is a procedure to remove fluid from the belly cavity.

How To Prepare

Tell your doctor if you have had a barium enema or upper GI (gastrointestinal) tests within the past 2 days. Barium that stays in the intestines can affect the results of the ultrasound.

You may need to prepare in other ways too. It depends on what test you are having. For example:

• If you are having your liver, gallbladder, spleen, and pancreas checked, you may need to eat a fat-free meal on the evening before the test. Then you may need to avoid eating for 8 to 12 hours before the test.
• For a test of the kidneys, you may be asked to drink 4 to 6 glasses of liquid about an hour before the test. This is to fill your bladder. You may need to avoid eating for 8 to 12 hours before the test to avoid gas buildup in the intestines. Gas could affect the results of the kidney ultrasound.
• If you are having your aorta checked, you may need to avoid eating for 8 to 12 hours before the test.

How It Is Done

The test is done by a radiologist. This is a doctor who has special training to perform and interpret imaging tests. Sometimes an ultrasound technologist (sonographer) will do the test. In that case, a radiologist will supervise. The test is done in an ultrasound room in a hospital or doctor's office.

You may need to take off your jewelry. You may also need to take off all or most of your clothes. It depends on which area is being examined. You will be given a cloth or paper to cover yourself during the test.

During the test

You will lie on your back (or on your side) on a padded exam table. Warmed gel will be spread on your belly or back to help the sound waves work best. A small handheld device (transducer) is pressed against your belly.

You may be asked to change positions so more scans can be done. For a kidney ultrasound, you may be asked to lie on your stomach.

You need to lie very still while the test is being done. You may be asked to take a breath and hold it for several seconds during the test. This lets the person doing the test see organs and structures more clearly.

The test usually takes 30 to 60 minutes.

After the test

You may be asked to wait until the radiologist has reviewed the images. He or she may want to take more views of some areas of your belly.

How It Feels

The gel may feel cold when it is put on your skin. But the gel may be warmed to body temperature first. You will feel light pressure from the transducer as it passes over your belly. Most people do not feel pain during the test. But if the test is being done to check damage from a recent injury, the slight pressure of the transducer may be somewhat painful. You will not hear or feel the sound waves.

What Affects the Test

You may not be able to have the test, or the results may not be helpful, if:

• Stool, air (or other gas), or contrast material (such as barium) is in the stomach or intestines.
• You cannot stay still during the test.
• You are extremely overweight.
• You have an open or bandaged wound in the area being viewed.

What To Think About

• You may need other tests, such as a CT scan, to follow up after the ultrasound. To learn more, see the topic Computed Tomography (CT) Scan of the Body.
• In rare cases, gallstones may not be found by ultrasound. Other imaging tests may be done if gallstones are suspected but not seen by the ultrasound.
  • Gallbladder Scan
  • Endoscopic Retrograde Cholangiopancreatogram (ERCP)
  • Abdominal X-Ray
• An ultrasound test can't tell if a solid tumor is cancerous (malignant) or noncancerous (benign). A biopsy test may be needed if a tumor is found. Ultrasound may be used during the biopsy. It helps guide the placement of the needle.
• Ultrasound costs less than other tests that take pictures of the organs in the belly. But for some problems, such as masses in the belly or an injury, a CT scan or MRI scan may be the better option. Your doctor may also suggest those tests if ultrasound results are normal but you still have belly pain.
  • Computed Tomography (CT) Scan of the Body
  • Magnetic Resonance Imaging (MRI) of the Abdomen