Super-resolution ultrasound imaging in heterogeneous media via multi-focal blind acoustical structured illumination

Objective.Conventional ultrasound imaging is constrained by the physical diffraction limit, creating a trade-off between resolution and penetration depth. While acoustical structured illumination (ASI) can surpass this limit, its efficacy relies on precise prior knowledge of illumination patterns. In clinical scenarios, tissue velocity inhomogeneity induces phase aberrations that disrupt intended patterns, causing traditional ASI to fail. This study aims to develop a blind acoustical structured illumination (B-ASI) method to achieve robust super-resolution in heterogeneous media without predefined field information.Approach. We utilize an intermediate variable to linearize the imaging model and employ an iterative ADMM optimization framework to reconstruct images based on the statistical stationarity of illumination patterns, facilitating the blind estimation of target structures under unknown field distortions.Main results. Simulations and phantom experiments show that B-ASI effectively overcomes the decoding failures of traditional ASI. B-ASI achieved a lateral full width at half maximum of 0.33 mm (a 34% improvement over plane wave imaging) and successfully resolved targets with 0.6 mm spacing in heterogeneous media environments. It significantly outperformed standard methods in both structural similarity index measure (0.67) and contrast-to-noise ratio (15.79 dB).Significance. This study provides a practical and effective solution for high-resolution ultrasonic structured acoustic illumination imaging in complex imaging media environments.