Abdominal Ultrasound


An abdominal ultrasound uses reflected sound waves to produce a picture of the organs and other structures in the upper abdomen. Occasionally a specialized ultrasound is ordered for a detailed evaluation of a specific organ, such as a kidney ultrasound. An abdominal ultrasound can evaluate the:

  • Abdominal aorta which is the large blood vessel (artery) that passes down the back of the chest and abdomen. The aorta supplies blood to the lower part of the body and the legs.

  • Liver, which is a large dome-shaped organ that lies under the rib cage on the right side of the abdomen. The liver produces bile (a substance that helps digest fat), stores sugars, and breaks down many of the body's waste products.

  • Gallbladder, which is a saclike organ beneath the liver. The gallbladder stores bile. When food is eaten, the gallbladder contracts, sending bile into the intestine.

  • Spleen, which is the soft, round organ that helps fight infection and filters old red blood cells. The spleen is located to the left of the stomach, just behind the lower left ribs.

  • Pancreas, which is the gland located in the upper abdomen that produces enzymes that help digest food. The digestive enzymes are then released into the intestines. The pancreas also releases insulin into the bloodstream; insulin helps the body utilize sugars for energy.

  • Kidneys, which are the pair of bean-shaped organs located behind the upper abdominal cavity. The kidneys remove wastes from the blood and produce urine.

A pelvic ultrasound evaluates the structures and organs in the lower abdominal area (pelvis).

 

Why It Is Done

Abdominal ultrasound is done to:

  • Determine the cause of abdominal pain.

  • Detect, measure, or monitor an aneurysm in the aorta. An aneurysm may cause a large, pulsing lump in the abdomen.

  • Evaluate the size, shape, and position of the liver. An ultrasound may be done to evaluate jaundice and other problems of the liver, including liver masses, cirrhosis, fat deposits in the liver (called fatty liver), or abnormal liver function tests.

  • Detect gallstones, inflammation of the gallbladder (cholecystitis), or blocked bile ducts.

  • Determine the size of an enlarged spleen and look for damage or disease.

  • Detect problems with the pancreas, such as pancreatitis or pancreatic cancer.

  • Determine the cause of blocked urine flow in a kidney. A kidney ultrasound may also be done to determine the size of the kidneys, detect kidney masses, detect fluid surrounding the kidneys, investigate causes for recurring urinary tract infections, or evaluate the condition of transplanted kidneys.

  • Determine whether a mass in any of the abdominal organs (such as the liver) is a solid tumor or a simple fluid-filled cyst.

Abdominal ultrasound is also done to:

  • Determine the condition of the abdominal organs after an accident or abdominal injury and look for blood in the abdominal cavity. However, computed tomography (CT) scanning is more commonly used for this purpose because it is more precise than abdominal ultrasound.

  • Guide the placement of a needle or other instrument during a biopsy.

  • Detect fluid buildup in the abdominal cavity (ascites). An ultrasound also may be done to guide the needle during a procedure to remove fluid from the abdominal cavity (paracentesis).

 

How To Prepare

Tell your doctor if you have had a barium enema or a series of upper GI (gastrointestinal) tests within the past 2 days. Barium that remains in the intestines can interfere with the ultrasound test.

Other preparations depend on the reason for the abdominal ultrasound test you are having.

  • For ultrasound of the liver, gallbladder, spleen, and pancreas, you may be asked to eat a fat-free meal on the evening before the test and then to avoid eating for 8 to 12 hours before the test.

  • For ultrasound of the kidneys, you may not need any special preparation. You may be asked to drink 4 to 6 glasses of liquid (usually juice or water) about an hour before the test to fill your bladder. You may be asked to avoid eating for 8 to 12 hours before the test to avoid gas buildup in the intestines. This could interfere with the evaluation of the kidneys, which lay behind the stomach and intestines.

  • For ultrasound of the aorta, you may need to avoid eating for 8 to 12 hours before the test.

 

How It Is Done

This test is done by a doctor who specializes in performing and interpreting imaging tests (radiologist) or by an ultrasound technologist (sonographer). It is done in an ultrasound room in a hospital or doctor's office.

You will need to remove any jewelry that might interfere with the ultrasound scan. You will need to take off all or most of your clothes, depending on which area is examined (you may be allowed to keep on your underwear if it does not interfere with the test). You will be given a cloth or paper covering to use during the test.

You will lie on your back (or on your side) on a padded examination table. Gel will be spread on your abdomen to improve the quality of the sound waves. The transducer is pressed against your abdomen and moved back and forth over it. A picture of the organs and blood vessels can be seen on a video monitor.

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

You need to lie very still while the ultrasound scan is being done. You may be asked to take a breath and hold it for several seconds during the scanning.

Abdominal ultrasound usually takes 30 to 60 minutes. You may be asked to wait until the radiologist has reviewed the information. The radiologist may want to do additional ultrasound views of some areas of your abdomen.

 

How It Feels

The gel may feel cold when it is applied to your stomach unless it is first warmed to body temperature. You will feel light pressure from the transducer as it passes over your abdomen. The ultrasound usually is not uncomfortable. However, if the test is being done to assess damage from a recent injury, the slight pressure of the transducer may be somewhat painful. You will not hear or feel the sound waves.

 

Risks

There are no known risks from having an abdominal ultrasound test.

 

Results

An abdominal ultrasound uses reflected sound waves to produce a picture of the organs and other structures in the abdomen. Your test results will be available within twenty-four (24) hours.

 

What Affects the Test

Factors that can interfere with your test and the accuracy of the results include:

  • Stool, air (or other gas), or contrast material (such as barium) in the stomach or intestines.

  • The inability to remain still during the test.

  • Extreme obesity.

  • Having an open wound in the area being viewed.