In abdominal ultrasound, a device called a transducer is passed lightly over your abdomen, directing high-frequency sound waves (ultrasound) at abdominal structures or organs. The sound waves are reflected back to the transducer and electronically converted into real-time images displayed on a viewing monitor. (These images may also be recorded on film or video and reviewed for abnormalities.)
Abdominal ultrasound may be used to examine the liver, gallbladder, bile ducts, spleen, pancreas, kidneys, ureters, bladder, and abdominal aorta. It is most helpful for visualizing organs that are uniform and solid, such as the liver, or fluid-filled, such as the gallbladder.
A technique called Doppler ultrasound may be used to evaluate blood circulation through abdominal blood vessels including the abdominal aorta, the largest blood vessel in the body, and veins in the abdomen, arms, legs and neck. In duplex scanning, this data is combined with standard ultrasound imaging to provide detailed information about abdominal blood vessels.
Purpose of the Abdominal Ultrasound
- To determine the size, shape, and position of organs in the abdominal cavity
- To detect tumors, abscesses, cysts, organ enlargement, and other abnormalities affecting tissues and organs in the abdomen
- To detect stones in the gallbladder, bile ducts, or kidneys
- To detect an enlarging aneurysm (abnormal outpouching) in the abdominal aorta
- To diagnose the presence of excess fluid in the abdomen (ascites)
- To evaluate the spleen after trauma to the abdomen
- To monitor a transplanted kidney
- To diagnose a hernia
- To examine ovaries, uterus and/or a fetus
- To guide the placement of biopsy needles or other instruments in various medical procedures
Who Performs Abdominal Ultrasound
- A radiologist, a sonographer or a technician who is trained in ultrasound
Special Concerns about Abdominal Ultrasound
- Because residual barium in the stomach or colon can distort sound waves and affect the test results, this exam should be done before any barium contrast x-rays are performed.
- The presence of gas or feces in the bowel can prevent adequate visualization of some regions of the abdomen.
- Ultrasound may fail to accurately show the boundaries between organs and tissue structures in dehydrated patients because of deficient body fluids.
- This test may be difficult in very obese patients, since fat may interfere with transmission of sound waves.
Before the Abdominal Ultrasound
- If you are having an ultrasound exam of the gallbladder, liver, pancreas, spleen, or abdominal aorta, you must fast for 8 to 12 hours before the procedure; in addition, the evening meal before a gallbladder ultrasound test should be fat-free.
- If you are having an ultrasound exam of the kidney, you must drink four to six glasses of liquid about an hour before the test. You must fast for 8 to 12 hours before the test to minimize the amount of gas in the intestines.
- Just before the test, you will be asked to disrobe and put on a hospital gown.
What You Experience
- You will lie on an examination table, either on your back or on your stomach, depending on the organ to be studied.
- A water-soluble gel is applied to your skin to enhance sound wave transmission.
- The examiner then moves the transducer back and forth over your abdomen to obtain different views of the targeted organs.
- You may be asked to hold your breath and to assume different positions during the test.
- Once clear images are obtained, they are recorded on film or video for later analysis.
- The procedure takes less than 30 minutes.
Risks and Complications of Abdominal Ultrasound
- Ultrasound is painless, noninvasive, and involves no exposure to radiation. There are no associated risks.
After the Abdominal Ultrasound
- The examiner removes the conductive gel from your skin.
- You are free to resume your normal diet and activities.
Abdominal Ultrasound Results
- A physician reviews the recorded images and video for evidence of any abnormality.
- If a definitive diagnosis can be made, appropriate treatment will be initiated.
- If ultrasound fails to yield a definitive diagnosis, other, more invasive diagnostic tests may be needed to provide more specific information or to further evaluate abnormal findings.
The Johns Hopkins Consumer Guide to Medical Tests
Simeon Margolis, M.D., Ph.D., Medical Editor
Updated by Remedy Health Media