What is an abdominal ultrasound?
An abdominal ultrasound is a procedure used to assess the organs and structures within the abdomen (belly). This includes the liver, gallbladder, pancreas, bile ducts, spleen, and abdominal aorta. Ultrasound allows your doctor to easily view the abdominal organs and structures from outside the body. Ultrasound may also be used to assess blood flow to abdominal organs.
An abdominal ultrasound uses a handheld probe called a transducer. It sends out ultrasonic sound waves at a frequency too high to be heard. When the transducer is placed on the abdomen at certain locations and angles, the sound waves move through the skin and other body tissues to the organs and structures of the abdomen. The sound waves bounce off the organs like an echo and return to the transducer. The transducer picks up the reflected waves, which are then converted into an electronic picture of the organs.
Different types of body tissues affect the speed at which sound waves travel. Sound travels the fastest through bone tissue, and moves most slowly through air. The speed at which the sound waves are returned to the transducer, as well as how much of the sound wave returns, is translated by the transducer as different types of tissue.
Prior to the procedure, clear, water-based gel is applied to the skin. This allows the transducer to move smoothly over the skin. It also helps remove any air between the skin and the transducer.
An ultrasound can also be used to assess blood flow within the abdomen. The ultrasound transducer that does this contains a Doppler probe. The Doppler probe evaluates the speed and direction of blood flow in vessels by making the sound waves easy to hear. The degree of loudness of the sound waves indicates the rate of blood flow within a blood vessel. Absence or faintness of these sounds may mean there is a blockage of blood flow.
Why might I need an abdominal ultrasound?
Abdominal ultrasound may be used to assess the size and location of organs and structures in the abdomen (belly). It can also be used to check the abdomen for conditions such as:
- Cysts (collections of fluid)
- Abscesses (collections of pus)
- Fluid build-up
- Clots in blood vessels
The size of the abdominal aorta can be measured by ultrasound. This may be done to detect an aortic aneurysm (ballooning and weakening of the blood vessel). Stones in the gallbladder, kidneys, and ureters may also be found with ultrasound.
Abdominal ultrasound may be used to guide needles used to biopsy (remove a piece of abdominal tissue for testing) or to drain fluid from a cyst or abscess.
This procedure can be used to assess blood flow within the abdomen.
There may be other reasons for your doctor to recommend an abdominal ultrasound.
What are the risks of an abdominal ultrasound?
There is no radiation used and generally no discomfort caused by moving the ultrasound transducer over the skin. Ultrasound may be safely used during pregnancy or in people with allergies to contrast dye, because no radiation or contrast dyes are used.
There may be risks depending on your specific medical condition. Be sure to discuss any concerns with your doctor before the procedure.
Certain factors or conditions may interfere with the results of the test. These include:
- Severe obesity
- Barium within the intestines from a recent barium procedure
- Intestinal gas
How do I get ready for an abdominal ultrasound?
- Your doctor will explain the procedure to you and you can ask questions.
- You may be asked to sign a consent form that gives your permission to do the procedure. Read the form carefully and ask questions if anything is not clear.
- Any prior preparation, such as fasting (not eating) or sedation (using drugs to make you sleepy), will be determined by the specific area to be examined. Your doctor will give you instructions if needed.
- Although the gel applied to the skin during the procedure does not stain clothing, you may want to wear older clothing, as the gel may not be completely removed from your skin afterwards.
- Based on your medical condition, your doctor may request other specific preparation.
What happens during an abdominal ultrasound?
An abdominal ultrasound may be done on an outpatient basis or as part of your stay in a hospital. Procedures may vary depending on your condition and your doctor's practices.
Generally, an abdominal ultrasound follows this process:
- You will be asked to remove any clothing, jewelry, or other objects that may interfere with the scan.
- If asked to remove clothing, you will be given a gown to wear.
- You will lie on an exam table. You will lie either on your side or on your stomach, depending on the specific area of the abdomen (belly) to be examined.
- A clear, water-based gel will be put on the skin over your belly.
- The transducer will be pressed against the skin and moved around over the area being studied.
- If blood flow is being assessed, you may hear a "whoosh, whoosh" sound when the Doppler probe is used.
- Once the procedure has been completed, the gel will be wiped off.
While the abdominal ultrasound procedure itself causes no pain, having to lie still for the length of the procedure may cause slight discomfort, and the gel may feel cool and wet. The technologist will use all possible comfort measures and complete the procedure as quickly as possible to minimize any discomfort.
What happens after an abdominal ultrasound?
There is no special care required after an abdominal ultrasound. You may go back to your usual diet and activities unless your doctor tells you differently.
Your doctor may give you other instructions after the procedure, depending on your particular situation.
Next stepsBefore you agree to the test or the procedure make sure you know:
- The name of the test or procedure
- The reason you are having the test or procedure
- The risks and benefits of the test or procedure
- When and where you are to have the test or procedure and who will do it
- When and how will you get the results
- How much will you have to pay for the test or procedure