ABSTRACT
The amplitude of an ultrasound pulse generally refers to the maximum peak-to-peak voltage of the received electrical signal. The propagation material offers a resistance to the passage of ultrasound, analogous to the electrical resistance to the flow of electrical charge along a wire. The behaviour of an ultrasound wave at an interface explains why coupling is an important requirement for the ultrasonic assessment of tissues. The majority of clinical applications of ultrasound are related to the imaging of soft tissue structures using a pulse–echo technique. Rectilinear mechanical scanning has been implemented for ultrasound assessment of the calcaneus, providing images of velocity and Broadband ultrasound attenuation data, from which values within a defined region of interest may be reported. There is a growing interest in the use of phalangeal ultrasound and calcaneal ultrasound to assess bone status in rheumatoid arthritis patients.
