Abdominal ultrasound is an imaging procedure used to examine the internal organs of the abdomen, including the liver, gallbladder, spleen, pancreas, and kidneys. The blood vessels that lead to some of these organs can also be looked at with ultrasound.

An ultrasound machine creates images that allow various organs in the body to be examined. The machine sends out high-frequency sound waves, which reflect off body structures to create a picture. A computer receives these reflected waves and uses them to create a picture. Unlike with x-rays or CT scans, there is no ionizing radiation exposure with this test.

You will be lying down for the procedure. A clear, water-based conducting gel is applied to the skin over the abdomen. This helps with the transmission of the sound waves. A handheld probe called a transducer is then moved over the abdomen.

You may be asked to change position so that the health care provider can examine different areas. You may also be asked to hold your breath for short periods of time during the examination.

The procedure usually takes less than 30 minutes.

Preparation for the procedure depends on the nature of the problem and your age. Usually patients are asked to not eat or drink for several hours before the examination. Your health care provider will advise you about specific preparation.

There is little discomfort. The conducting gel may feel slightly cold and wet.

Your health care provider may order this test to:

• Determine the cause of abdominal pain
• Learn why there is swelling of an abdominal organ
• Look for stones in the gallbladder or kidney

The specific reason for the test will depend on your symptoms.

The organs examined are normal in appearance.

The significance of abnormal results depends on the organ being examined and the nature of the problem. You should consult your health care provider with any questions and concerns.

Many possible conditions could be revealed by an abdominal ultrasound. Some of these include:

• Abdominal aortic aneurysm
• Cholecystitis
• Gallstones
• Hydronephrosis
• Kidney stones
• Spleen enlargement (splenomegaly)
• Pancreatitis

There is no documented risk. No ionizing radiation exposure is involved.

Cosgrove DO, Meire HB, Lim A, Eckersley RJ. Ultrasound: general principles. In: Grainger RC, Allison D, Adam, Dixon AK, eds. Diagnostic Radiology: A Textbook of Medical Imaging. 5th ed. New York, NY: Churchill Livingstone; 2008:chap 3.

Pickhardt PJ. Diagnostic imaging procedures in gastroenterology. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 13.