Ultrasonography, which is sometimes called sonography, uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs. The sound waves bounce off body parts and send back an image, like sonar on a submarine. A computer then looks at the signals sent back by the sound waves and creates an image of the body using those signals.

Ultrasounds are used to view internal organs as they function, and to assess blood blow through various vessels. Ultrasound procedures are often used to examine many parts of the body such as the abdomen, breasts, female pelvis, prostate, scrotum, thyroid and parathyroid, and the vascular system. During pregnancy, ultrasounds are performed to evaluate the development of the fetus.