Application of eigen-spaced beamformers for imaging lamina of vertebral arch

Ultrasound (US) has been proposed as a guidance tool for spinal intervention. However, bone structures are often visualized poorly in the standard US images which is based on the delay and sum beamforming method (DAS). In this study, we investigate combination of an eigenspace based beamformer (ESMV) with the phase symmetry (PS) post-processing technique to extract the lamina surface from ultrasound images. Thereby, in simulation, and in-vivo studies we show that an ESMV beamformer with a rank-1 signal subspace, can keep the bone structure and improve the edges, despite some distortion of the speckle pattern. The PS images obtained from this beamformer setup have sharper bone boundaries compared with the DAS ones.