Zone acquisition imaging as an alternative to line-by-line acquisition imaging

Abstract

Objective: The aim of this study is to design an imaging system that overcomes echo data time constraints imposed by the speed of sound in tissue on the rate of image acquisition.Methods: An ultrasound system was designed, which utilizes a novel method of echo acquisition and image formation. Using a programmable pulse generator, the desired field of view is insonified with less than 10 pulse-echo cycles per frame instead of the normal 100–200 pulse-echo cycles. On receive, phase and amplitude echo data (RF) from individual transducer elements are stored in a channel domain memory. High-speed microprocessors perform a de-convolution algorithm, which includes all mathematical operations for element phase correction, focusing, apodization, and other image formation functions, and stores the resulting echo location data using an x-y or some other suitable coordinate system. Echo location data are then processed using conventional techniques to generate an image for display, storage, or network distribution.Results: Images have been produced in all modes using techniques such as synthetic aperture, pulse inversion, coded excitation, and others and are characterized by high spatial resolution with reduced motion artifacts. Because all data are acquired with only a few pulse-echo cycles and each frame is processed as a whole, the rate of image formation is directly related to image processor speed. With less than 10 pulse-echo cycles per frame, the electronics operate at much lower power levels, enabling major miniaturization and practical battery operation of the scanner.Conclusions: A fundamentally different strategy for image acquisition has been developed that utilizes more information embedded in received data. It overcomes velocity propagation constraints that limit image acquisition requirements and takes full advantage of progress in microprocessors for electronic array focusing. Objective: The aim of this study is to design an imaging system that overcomes echo data time constraints imposed by the speed of sound in tissue on the rate of image acquisition. Methods: An ultrasound system was designed, which utilizes a novel method of echo acquisition and image formation. Using a programmable pulse generator, the desired field of view is insonified with less than 10 pulse-echo cycles per frame instead of the normal 100–200 pulse-echo cycles. On receive, phase and amplitude echo data (RF) from individual transducer elements are stored in a channel domain memory. High-speed microprocessors perform a de-convolution algorithm, which includes all mathematical operations for element phase correction, focusing, apodization, and other image formation functions, and stores the resulting echo location data using an x-y or some other suitable coordinate system. Echo location data are then processed using conventional techniques to generate an image for display, storage, or network distribution. Results: Images have been produced in all modes using techniques such as synthetic aperture, pulse inversion, coded excitation, and others and are characterized by high spatial resolution with reduced motion artifacts. Because all data are acquired with only a few pulse-echo cycles and each frame is processed as a whole, the rate of image formation is directly related to image processor speed. With less than 10 pulse-echo cycles per frame, the electronics operate at much lower power levels, enabling major miniaturization and practical battery operation of the scanner. Conclusions: A fundamentally different strategy for image acquisition has been developed that utilizes more information embedded in received data. It overcomes velocity propagation constraints that limit image acquisition requirements and takes full advantage of progress in microprocessors for electronic array focusing.