What is an ultrasound?
Ultrasound, also known as sonography, or ultrasonography, is a diagnostic procedure that transmits high-frequency sound waves, inaudible to the human ear, through body tissues. The echoes are recorded and transformed into video or photographic images of the internal structures of the body.
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 gall bladder, liver, heart, kidney, female reproductive organs -- and even of fetuses still in the womb. Ultrasound can also detect blockages in the blood vessels.
Ultrasound may be used with other diagnostic procedures or by itself.
Are there any side effects?
Studies have shown that ultrasound is not hazardous. There are no harmful side effects. In addition, ultrasound does not use radiation, as x-ray tests do.
Before the test
The preparation for this test will depend on the type of ultrasound procedure your doctor has ordered. Some preparations include drinking a quart of water before the test to obtain better images. Other preparations may include eating a fat-free dinner the night before the test, or possibly fasting.
The physician, nurse or receptionist will give you complete instructions prior to the exam.
On the day of the test
- Please do not bring valuables such as jewelry and credit cards.
- Your ultrasound test is performed by a certified, specially trained technologist and results are interpreted by a board-certified radiologist.
- You may be asked to change into a hospital gown.
During the test
- You will be asked to lie on a comfortable table, either on your side or on your back.
- A small amount of water-soluble gel is applied to the skin over the area to be examined. The gel does not harm your skin or stain your clothes.
- A hand-held instrument, called a transducer, is placed against the gel on your body. The transducer will be moved back and forth across the area being examined.
- The technologist will instruct you when, if necessary, to hold your breath to prevent motion on the images.
- The technologist does not interpret the images, but rather, takes the images for the radiologist to review for diagnosis.
- A radiologist may also review the images on the screen during the examination with the technologist.
- After the procedure is complete, the technologist will wipe off any remaining gel used during the procedure.
- The ultrasound test usually takes from 30 to 60 minutes to complete.
After the test
The images will be reviewed by a radiologist. A written report of the radiologist's findings will be forwarded to your referring physician, either by fax or mail. Your physician will discuss the test results with you.
- Radiological Society of North America. American College of Radiology. Ultrasound-General Accessed 3/20/2014.
- U.S. Food and Drug Administration. Taking a Close Look at Ultrasound Accessed 3/20/2014.
- Jacobson FL, McKean SC. Chapter 105. Introduction to Radiology. In: McKean SC, Ross JJ, Dressler DD, Brotman DJ, Ginsberg JS. eds. Principles and Practice of Hospital Medicine. New York: McGraw-Hill; 2012.library.ccf.org Accessed March 20, 2014.
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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: 3/19/2014...#4995