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.
Your preparation will depend on the part of the body being examined.
Most of the time, ultrasound procedures do not cause discomfort. The conducting gel may feel a little cold and wet.
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.
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.
Butts C. Ultrasound. In: Roberts JR, Custalow CB, Thomsen TW, eds. Roberts and Hedges' Clinical Procedures in Emergency Medicine and Acute Care. 7th ed. Philadelphia, PA: Elsevier; 2019:chap 66.
Fowler GC, Lefevre N. Emergency department, hospitalist, and office ultrasound (POCUS). In: Fowler GC, ed. Pfenninger and Fowler's Procedures for Primary Care. 4th ed. Philadelphia, PA: Elsevier; 2020:chap 214.
Merritt CRB. Physics of ultrasound. In: Rumack CM, Levine D, eds. Diagnostic Ultrasound. 5th ed. Philadelphia, PA: Elsevier; 2018:chap 1.
Reviewed By: Jason Levy, MD, Northside Radiology Associates, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.