An ultrasound test is a radiology technique, which employs high-frequency sound waves to produce images of the organs and structures of the human body. Ultrasound scanners consist of a computer, a display screen and a transducer probe that is used to scan the body. The transducer is a small hand-held gadget attached to the scanner. It is directly placed on top of the area to be scanned, on which a lubricating gel has been applied. The sound waves that are transmitted by the transducer through the body are then reproduced by internal structures as "echoes." These echoes return to the transducer and are sent electrically onto a display screen, and exhibited as real-time visual images.

Ultrasound pictures are based on the same theories involved in the sonar used by bats, ships at sea and anglers with fish detectors. As a controlled sound bounces against objects, its echoing waves can be used to perceive the distance of the object is, its shape, size, and its internal consistency. When the transducer is pressed against the skin, it directs a stream of muted, high frequency sound waves into the body. As the sound waves echo from the body's fluids and tissues, the transducer records tiny changes in the sound's pitch and direction. These waves are instantly measured and displayed by a computer, which in turn generates a real-time picture on the display screen.

Ultrasound pictures are a good method for guiding minimally invasive procedures and a useful diagnostic instrument in Obstetrics. Additionally, these pictures are valuable means of examining the body to detect problems with muscles, tendons, ligaments, joints and soft tissue. Ultrasound images often demonstrate movement, function and anatomy, in addition to allowing radiologists to analyse a multiplicity of conditions and assess damage after an injury or illness. Most examinations take 45 minutes or less.