Ultrasound uses sound waves and a computer to create images of internal organs and blood vessels and to monitor the progress of a pregnancy. A tool called a transducer, which emits sound waves, is placed over the area of the body being examined. The sound waves that are reflected back and the echoes are received by the transducer, which thereafter sends the information to a computer. A computer analyzes the signals, creates and displays a real-time image on a screen. We can also produce a 3D/4D coloured image composition.