Ultrasound
Ultrasound uses high-frequency sound waves to make images of organs and structures inside the body.
How the Test is Performed
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.
x-ray
X-rays are a type of electromagnetic radiation, just like visible light. An x-ray machine sends individual x-ray waves through the body. The images...

CT scan
A computed tomography (CT) scan is an imaging method that uses x-rays to create pictures of cross-sections of the body. Related tests include:Abdomin...

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. You will feel the sonographer press the ultrasound probe against your body in the area they are reviewing.
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:
- Arteries in the neck
Arteries in the neck
Intravascular ultrasound (IVUS) is a diagnostic test. This test uses sound waves to see inside blood vessels. It is useful for evaluating the coron...
ImageRead Article Now Book Mark Article - Veins or arteries in the arms, legs, or abdomen
Veins or arteries in the arms, legs
This test uses ultrasound to look at the blood flow in the large arteries and veins in the arms or legs.
ImageRead Article Now Book Mark Article - Pregnancy
Pregnancy
A pregnancy ultrasound is an imaging test that uses sound waves to create a picture of how a baby is developing in the womb (uterus). It is also use...
ImageRead Article Now Book Mark Article - Pelvis
Pelvis
A pelvic (transabdominal) ultrasound is an imaging test. It is used to examine organs in the pelvis.
Read Article Now Book Mark Article - Abdomen and kidneys
Abdomen and kidneys
Abdominal ultrasound is a type of imaging test. It is used to look at organs in the abdomen, including the liver, gallbladder, pancreas, and kidneys...
ImageRead Article Now Book Mark Article - Breast
Breast
Breast ultrasound is a test that uses sound waves to examine the breasts.
ImageRead Article Now Book Mark Article - Thyroid
Thyroid
A thyroid ultrasound is an imaging method to see the thyroid, a gland in the neck that regulates metabolism (the many processes that control the rate...
ImageRead Article Now Book Mark Article - Eye and orbit
Eye and orbit
An eye and orbit ultrasound is a test to look at the eye area. It also measures the size and structures of the eye.
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Normal Results
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.
Risks
There are no known risks. The test does not use ionizing radiation.
Considerations
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.
Reviewed By
Jason Levy, MD, FSIR, Northside Radiology Associates, Atlanta, GA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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.
Morris AE, Adamson R, Frank J. Ultrasonography: principles and basic thoracic and vascular imaging. In: Broaddus VC, Ernst JD, King TE, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine. 7th ed. Philadelphia, PA: Elsevier; 2022:chap 23.
Zhang D, Kahlili K, Yu H, Levine D. Physics of ultrasound. In: Rumack CM, Levine D, eds. Diagnostic Ultrasound. 6th ed. Philadelphia, PA: Elsevier; 2024:chap 1.