How is an ultrasound image produced?
A transducer (ultrasound probe) is placed against the body over the site that is to be imaged. It produces sound waves that travel into the body. The sound waves bounce off of structures inside the body, and return to the transducer, which sends the information to the computer. The computer interprets the information and converts the returned echoes into pictures. It does this by timing how long it takes for the sound waves to return to the transducer. If the echoes take a longer time, their information is placed on the bottom of the image, so they appear farther away from the transducer location. Faster-returning echoes are placed at the top of the image, closer to the transducer location. Ultrasound cannot image through bone or air, so, for example, the brain (inside the skull), the lungs, and in most cases the intestines, cannot be imaged with ultrasound. Ultrasound images can provide information about structural abnormalities inside the body. They can locate tumors, bleeding, abnor
