3-D Ultrafast Imaging Using a 3072-Element Matrix Array

The 3-D ultrafast imaging holds great potential across multiple applications, including blood flow imaging, elastography, brain functional ultrasound, cardiac imaging, and microvascular flow imaging. Despite promising preclinical results, extending these results to human-scale organs remains a major challenge due to the limited aperture and channel count of existing fully addressed arrays, which constrain depth penetration, field of view, and resolution. In this work, we developed a new research platform for 3-D ultrafast imaging of human-scale organs using a fully connected 3072-element matrix array. The probe has an aperture of $22.4\times 15.9$ mm2, which enables deeper penetration and higher lateral resolution compared to smaller arrays. The platform is driven by two synchronized 512-channel systems, providing a total of 1024 electronic channels, each with a 4:1 multiplexer. We evaluated the system's performance using numerical simulations and experiments on phantoms, which showed that the 3072-element array provided a significant increase in lateral resolution-56% in azimuth and 39% in elevation at a depth of 50 mm-compared to a standard 1024-element matrix array. The larger aperture also allowed for better penetration depth, reaching approximately 110 mm. We investigated different 3-D ultrafast imaging strategies with diverging waves. A synthetic aperture imaging approach using subapertures in both transmit and receive provided the best imaging performance in terms of lateral resolution, field of view, and contrast. The translational potential of the platform was successfully validated in vivo on swine kidneys and livers, demonstrating the feasibility of 3-D ultrafast Doppler and 3-D ultrasound localization microscopy (ULM) for visualizing anatomical structures and microcirculation.