Recursive Aperture Decoded Ultrasound Imaging (READI) With Estimated Motion-Compensated Compounding (EMC2)

Abstract: Fast Orthogonal Row-Column Electronic Scanning (FORCES) is a Hadamard-encoded Synthetic Transmit Aperture (STA) imaging sequence using bias-sensitive Top-Orthogonal to Bottom Electrode (TOBE) arrays. It produces images with a higher Signal-to-Noise Ratio (SNR) and improved penetration depth compared to traditional STA techniques, but suffers from motion sensitivity due to ensemble size and aperture encoding. This work presents Recursive Aperture Decoded Ultrasound Imaging (READI), a novel decoding and beamforming technique for FORCES that produces multiple low-resolution images out of subsets of the FORCES sequence that are less susceptible to motion, but sum to form the complete FORCES image. Estimated Motion-Compensated Compounding (EMC2) describes the process of comparing these low-resolution images to estimate the underlying motion, then warping them to align before coherent compounding. READI with EMC2 is shown to fully recover images corrupted by probe motion, and restore tissue speckle and sharpness to an image of a beating heart. READI low-resolution images by themselves are demonstrated to be a marked improvement over sparse STA schemes with the same transmit count, and are shown to recover blood speckle at a flow rate of 42 cm/s.