Ultrasound: MedlinePlus Medical Encyclopedia

P Ultrasound uses high-frequency sound waves to make images of organs and structures inside the body.

T How the Test is Performed
P 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.
P 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.

T How to Prepare for the Test
P Your preparation will depend on the part of the body being examined.

T How the Test will Feel
P Most of the time, ultrasound procedures do not cause discomfort. The conducting gel may feel a little cold and wet.

T Why the Test is Performed
P The reason for the test will depend on your symptoms. An ultrasound test may be used to identify problems involving:
- Arteries in the neck
- Veins or arteries in the arms or legs
- Pregnancy
- Pelvis
- Abdomen and kidneys
- Breast
- Thyroid
- Eye and orbit

T Normal Results
P Results are considered normal if the organs and structures being examined look OK.

T What Abnormal Results Mean
P 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.

T Risks
P There are no known risks. The test does not use ionizing radiation.

T Considerations
P 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.

T Alternative Names
P Sonogram

T Images
- Abdominal ultrasound
- Ultrasound in pregnancy
- 17 week ultrasound
- 30 week ultrasound
- Carotid duplex
- Ultrasound comparison
- Thyroid ultrasound
- Ultrasound
- Ultrasound, normal fetus- ventricles of brain
- 3D ultrasound

T References
P Butts C. Ultrasound. In: Roberts JR, ed. Roberts and Hedges' Clinical Procedures in Emergency Medicine. 6th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 66.
P 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. New York, NY: Elsevier; 2015:chap 3.

T Review Date 7/3/2016
P Updated by: Jason Levy, MD, Northside Radiology Associates, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

