Ultrasound uses high-frequency sound waves to make images of organs and structures inside the body.
An ultrasound machine makes images so that organs inside the body can be examined. The machine sends out high-frequency sound waves, which reflect off body structures. A computer receives the waves and uses them to create a picture. Unlike with an x-ray or CT scan, this test does not use ionizing radiation.
The test is done in the ultrasound or radiology department.
- You will lie down for the test.
- A clear, water-based gel is applied to the skin on the area to be examined. The gel helps with the transmission of the sound waves.
- A handheld probe called a transducer is moved over the area being examined. You may need to change position so that other areas can be examined.
How to Prepare for the Test
Your preparation will depend on the part of the body being examined.
How the Test will Feel
Most of the time, ultrasound procedures do not cause discomfort. The conducting gel may feel a little cold and wet.
Why the Test is Performed
The reason for the test will depend on your symptoms. An ultrasound test may be used to identify problems involving:
Results are considered normal if the organs and structures being examined look OK.
What Abnormal Results Mean
The meaning of abnormal results will depend on the part of the body being examined and the problem found. Talk to your health care provider about your questions and concerns.
There are no known risks. The test does not use ionizing radiation.
Some types of ultrasound tests need to be done with a probe that is inserted into your body. Talk to your provider about how your test will be done.
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Merritt CRB. Physics of ultrasound. In: Rumack CM, Levine D, eds. Diagnostic Ultrasound. 5th ed. Philadelphia, PA: Elsevier; 2018:chap 1.
Cosgrove DO, Eckersley RJ, Harvey CJ, Lim A. Ultrasound. In: Adam A, Dixon AK, Gillard JH, Schaefer-Prokop CM, eds. Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging. 6th ed. Philadelphia, PA: Elsevier; 2015:chap 3.