Understanding the Contribution of Adaptive Beamforming Combined with Ultrasound Localisation Microscopy for Super-Resolved Microvessel Mapping

Super-resolution ultrasound imaging (SRUI) has been established to overcome the ultrasound imaging diffraction limit in mapping the vascular bed. The beamforming currently used is suitable for B-mode imaging and little is known of its suitability to generate images that are subsequently processed using SRUI algorithms. This theoretical study will use a two-parallel vessel phantom to investigate the performance of minimum variance beamformers (MV BF), that are known to provide improved lateral resolution, as combined with Ultrasound Localisation Microscopy (ULM). This is compared to conventional delay and sum (DAS) beamformers. The aim is to assess vessel recovery performance using the different beamformers and investigate the link with MB localisation performance. microvessel position definition and corresponding vessel separation estimation compared to conventional DAS BFs. The MV BF was shown to provide improvement in localisation uncertainty and vessel recovery specifically for vessel separations between 1-4 λ compared to the DAS, which showed artefact vessels at this distance range. In conclusion, the MV BF is proposed as a more suitable adjunct to ULM compared to the DAS.