What is Ultrasonography?
In ultrasonography (also called ultrasound), high-frequency sound waves, inaudible to the human ear, are transmitted through body tissues. These sound waves are reflected back to a receiver by the tissues, and the echoes vary according to the tissue density. The echoes are recorded and translated into video or photographic images that are displayed on a monitor.
An ultrasound may be performed over the skin (transcutaneous), or an endoscope (small ultrasound probe) may be placed within an organ such as the stomach or colon (endosonography).
Ultrasound images help in the diagnosis of a wide range of diseases and conditions. The idea for ultrasonography came from sonar technology, which makes use of sound waves to detect underwater objects.
Ultrasound is used to create images of soft tissue structures, such as the intestinal tract, gallbladder, liver, heart, kidneys, pancreas, bladder, thyroid glands, prostate, rectum and sphincter muscles, female reproductive organs, and even of babies in the uterus. Ultrasound can also measure the flow of blood in the arteries to detect blockages.
Ultrasound may be used to detect the following:
- Fluid-filled structures called cysts, or solid growths, that may be present in a variety of organs
- Abnormal size or density of an organ
- The depth of invasion of a gastrointestinal cancer
- Abnormal lymph nodes
- Gallstones
- Anal sphincter damage (the anal sphincter is the muscle that controls bowel movements)
- Abnormal blood vessels called varices
Ultrasound cannot be used to view bones because they are too dense for the sound waves to penetrate. In addition, some organs may not be well identified with ultrasound because air or gas interferes with the production of ultrasound images.
Ultrasound may be used as a diagnostic test or to guide a biopsy procedure.
Are there any side effects?
Studies have shown that ultrasound is not hazardous. There are no harmful side effects, and there is virtually no discomfort during the test. In addition, ultrasound does not use radiation, as do X-ray tests.
Before the test
Generally, no special preparation is needed for an ultrasound test.
During the test
Your ultrasound test is performed by registered, specially trained technologists or by physicians such as gastroenterologists, colorectal surgeons or radiologists. The ultrasound results are interpreted by a board-certified radiologist, colorectal surgeon, urologist or other specialist.
You will lie on a padded examination table. A small amount of water-soluble gel is applied over the area or in the organ (such as the rectum or vagina) to be examined. The gel does not harm your skin or internal organs and can be wiped off after the procedure.
A wand-like device called a transducer is gently applied against the skin or inserted into the organ. The transducer transmits high-frequency sound waves through body tissues and receives their echoes back again. The sound waves are translated into images on a monitor.
There is virtually no discomfort during the test. If a full bladder is required for the test, you may feel some discomfort when the transducer is applied.
You may be asked to hold your breath briefly several times.
The ultrasound test takes about 15-40 minutes to complete.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 6/2/2008…#9727
