ULTRASOUND DIAGNOSIS OF ITS PROPERTIES

Abstract

The imaging characteristics of diagnostic ultrasound (US) are determined by the ultrasonic properties of tissue. The velocity of propagation of US and the attenuation are the 2 most important parameters. These determine the frequency with which the tissues may be imaged, which in turn sets a fundamental limit on the axial and the lateral resolution. Ultrasonic imaging equipment is designed on the premise that the ultrasonic energy propagates through tissue in a straight line and that the ultrasonic beam is very narrow. In fact, the ultrasonic energy propagates through tissue as a beam of finite dimensions set by the physical dimensions of the transducer, the way it is constructed, and the way it is energized. Also, the velocity of propagation in different tissues varies and this can lead to deviation of the ultrasonic beam from the assumed direction of propagation