Hadamard-Based Recursive Aperture Decoded Ultrasound Imaging (READI) With Estimated Motion-Compensated Compounding (EMC2) Using Top-Orthogonal to Bottom Electrode (TOBE) Arrays

A research team from the University of Alberta has published a breakthrough in medical ultrasound imaging, introducing a combined technique called READI with EMC2. The system tackles a major flaw in high-quality synthetic aperture imaging, which uses Hadamard matrix encoding on advanced Top-Orthogonal to Bottom Electrode (TOBE) arrays: extreme sensitivity to motion. Even slight probe movement or internal organ motion can corrupt the final high-resolution image, limiting its clinical use for dynamic scans like echocardiograms.

The team's solution is a two-part process. First, Recursive Aperture Decoded Imaging (READI) is a novel decoding and beamforming method that generates several lower-resolution 'snapshots' from subsets of the full data sequence. These READI images are individually less degraded by motion. Second, the Estimated Motion-Compensated Compounding (EMC2) algorithm analyzes these snapshots to estimate the underlying motion, then warps and aligns them before combining them into a single, clear, high-resolution final image.

In practical tests, applying READI-EMC2 to a TOBE-based scanning sequence fully restored images ruined by deliberate probe motion. Most significantly, it recovered clear tissue speckle and boundaries in images of a physically simulated beating heart phantom—a scenario where traditional methods fail. The READI images alone also proved superior to older sparse encoding schemes, successfully visualizing blood speckle at a clinically relevant flow rate of 42 cm/s, paving the way for more robust cardiac and vascular imaging.