State-of-the-art of single-transducer ultrasonic imaging technology.
This paper attempts to take note of some recent improvements in ultrasound  echo-ranging technology and make some observations on the single versus multiple-transducer element approach. It would appear at this time that the problems encountered with visualization systems may not be solved by using multiple transducers per se, and that the unique advantages that accrue to the multiple-transducer systems have yet to demonstrate that they fulfill and important clinical need.
D014159:Transducers; D014465:Ultrasonics / Q000295:instrumentation*; D014463:Ultrasonography