Ultrasound instrumentation.

This article begins by reviewing the basic physical principles of ultrasound emphasizing those factors which control the resolution of the ultrasound image. It next proceeds to a discussion of the types of ultrasound instruments currently available for diagnostic use including their method of image production and focusing as well as the system utilized for creating a real-time image. The types of scanners currently available are then grouped by certain common characteristics and the strengths and weaknesses of each type of instrument is examined. There is also a discussion of specialized ultrasound scanners such as dedicated breast scanners and doppler instruments. Finally, the paper concludes with recommendations for the most suitable instrument for various clinical situations.