Theory of ultrasound physics and imaging

An image is a representation of specific properties of a physical object. In ultrasonic imaging, the properties that are imaged are related to the mechanical structure of the underlying tissue. Medical transducer technology has advanced over the last few decades with the development of novel materials, fabrication techniques, and approaches to transducer design. The quality of an ultrasound image is directly related to the quality of the transducer element. Once the transducer is excited, an ultrasonic waveform emerges from the transducer and must propagate through a medium. In terms of ultrasonic imaging, scattering modifies the frequency content of the signals returning to the receiver. Echographic images, also known as B‐mode images, are the most common image mode in biomedical ultrasound imaging and are produced from the beam formed radiofrequency data. The fundamental imaging mode for biomedical ultrasound is B‐mode imaging which relates greyscale intensity to structure shapes.