How does Ultrasound work?
An ultrasound machine has 3 key parts: a control panel, a display screen, and a transducer, which usually looks a lot like a microphone or a computer mouse. The transducer sends out sound waves and picks up the echoes. The doctor or ultrasound technologist moves the transducer over the part of the body being studied. The computer inside the main part of the machine analyzes the signals and puts an image on the display screen.
The shape and intensity of the echoes depend on how dense the tissue is. For example, most of the sound waves pass right through a fluid-filled cyst and send back very few or faint echoes, which makes them look black on the display screen. But the waves will bounce off a solid tumor, creating a pattern of echoes that the computer will show as a lighter-colored image.