Preserving speckle statistics in minimum-variance beamformed images: the effectiveness of spatial compounding

Data-dependent apodization techniques such as the minimum-variance beamformer (MVB) can beat the diffraction limit of the conventional Delay-and-Sum (DAS) beamformer, yielding enhanced resolution and contrast. However, the MVB algorithm strongly increases the speckle variance. This needs to be compensated in order for the MVB algorithm to be clinically successful. This paper shows that combining the MVB with spatial compounding yields unprecedented image quality with significantly increased lateral resolution and decreased clutter compared to conventional DAS imaging, without the drawback of increased speckle variance.