Delay multiply and sum beamforming in 3D coherent multi-transducer ultrasound for contrast enhancement in the presence of acoustic clutter

Transducers with larger aperture size are desirable in ultrasound imaging to improve resolution and image quality. However, in practice inhomogeneities and aberrating layers cause phase errors that limit the benefits of increased aperture size. A coherent multi-transducer ultrasound (CoMTUS) imaging system enables an extended effective aperture through coherent combination of multiple transducers. In this work, an implementation of the Filtered Delay Multiply and Sum (F-DMAS) beamforming algorithm adapted to the specific aperture of CoMTUS imaging, was applied to 3D experimental data acquired in the presence of acoustic clutter and aberration. Results show F-DMAS applied to CoMTUS data suppresses the acoustic clutter across the image, with an increased dynamic range and improved detection of point targets. When further combined with the optimal beamforming parameters of CoMTUS, the impact of phase aberration effects along with the acoustic clutter is further reduced.