A flexible annular array imaging platform for micro-ultrasound

Micro-ultrasound is an invaluable imaging tool for many clinical and preclinical applications with high resolution (about several tens microns). The imaging systems for micro-ultrasound are developed extensively in recent years including single element imaging systems, and linear array imaging systems. This paper presents the development of a novel programmable and real-time annular array imaging platform for micro-ultrasound. It supported multi-channel dynamic beamforming technique for large depth-of-field imaging. The major image processing algorithms were achieved by the novel field programmable technology for high speed and flexibility. Real-time imaging processing was achieved by fast processing algorithms and high speed data transfer interface. Extensive tests including hardware, algorithms, wire phantom, and tissue mimicking phantom measurements were conducted to demonstrate good performance of the platform. The calculated contrast-to-noise ratio (CNR) of the tissue phantom measurements were higher than 1.2 in the range of 3.8-8.7 mm imaging depth. The platform supported higher than 25 images per second for real-time image acquisition. The depth-of-field had about 2.5-fold improvement as opposed to single element transducer imaging.