Ultrasound (also called sonography) is a diagnostic medical procedure that uses high-frequency sound waves to produce dynamic visual images of organs, tissues or blood flow inside the body.  The high-frequency sound waves are transmitted to the area of interest and the returning echoes recorded.  This type of procedure is often referred to as a sonogram or ultrasound scan. 

Sonography can be used to examine many parts of the body, such as the abdomen, breasts, female reproductive system, prostate, heart and blood vessels and more.

In obstetrics ultrasound is used to study the age, number, and location of the fetus, as well as to examine the fetus for birth defects or other potential problems. In the abdomen, it is used to detect abnormalities such as gallstones or liver disease.  Heart disease can be identified through cardiac ultrasound.  Ultrasound can also be used for therapeutic purposes such as muscle/joint heating and lithotripsy.

Sonography is also used to guide fine-needle tissue biopsy to assist in taking a sample of cells from an organ for lab testing (for example, a test for cancer in breast tissue).