Motion-guided channel resampling for grating lobe suppression in plane-wave imaging.

Abstract

Objective: Plane-wave imaging (PWI) remains susceptible to grating lobe artifacts when arrays with relatively large element pitches are used. This study proposes motion-guided channel resampling for PWI (MCR-PWI) to suppress grating lobes by exploiting inter-frame motion without transducer modification or prescribed probe translation. Approach. Two consecutive coherently compounded acquisitions are combined using motion-guided channel resampling. After intra-acquisition phase compensation to reduce angle-dependent phase inconsistencies, lateral and axial inter-frame displacements are estimated from phase-compensated in-phase/quadrature data using normalized cross-correlation. These estimates guide channel-domain resampling and coherent synthesis during beamforming. Theoretical analysis predicts maximum first-grating-lobe suppression near a half-pitch lateral displacement. Performance was evaluated through numerical simulations, phantom experiments, and preliminary freehand thyroid and carotid imaging in one healthy volunteer. Main results. At a half-pitch lateral displacement, MCR-PWI reduced simulated mean grating lobe levels by 10.72 to 20.59 dB relative to conventional PWI under lateral-only motion and by 5.98 to 14.17 dB relative to phase-compensated PWI under combined lateral-axial motion. Phantom experiments demonstrated improved cyst contrast while maintaining comparable spatial resolution. Preliminary in-vivo imaging further showed reduced clutter and improved image contrast. Significance. MCR-PWI utilizes inter-frame motion to refine effective receive sampling and reduce grating lobe artifacts while preserving spatial resolution. The findings support its preliminary feasibility for freehand PWI. Performance depends on suitable displacement and reliable motion estimation, and further validation under broader motion conditions is required.