What is ultrasonography?

In ultrasonography, or ultrasound, high-frequency sound waves, inaudible to the human ear, are transmitted through body tissues. The echoes are recorded and transformed into video or photographic images.

Ultrasound images help in the diagnosis of a wide range of diseases and conditions. The idea for ultrasonography came from sonar technology, which makes use of sound waves to detect underwater objects.

Ultrasound is used to create images of soft tissue structures, such as the gall bladder, liver, heart, kidney, female reproductive organs-- and even of babies still in the womb. Ultrasound can also detect blockages in the blood vessels.

Ultrasound cannot be used to image bones because they are too dense to penetrate. In addition, the intestinal tract and normal lung tissue are not easily identified with ultrasound because air or gas interfere with the production of ultrasound images.

Ultrasound may be used with other diagnostic procedures or by itself.