Ultrasound compounding with automatic attenuation compensation using paired angle scans.

Variations in attenuation in tissue can result in shadowing and enhancement in ultrasound images. Angular compounding of ultrasound images by lateral beam-steering can be used to improve delineation of structures, but causes such shadows and enhancements to appear in less recognisable forms. We present an algorithm which uses lateral beam-steering to produce compounded images with significantly reduced artefacts, by considering the response from equal and opposite angles. This is compared to several other alternative algorithms for attenuation estimation, some of them embedded for the first time in a multi-angle framework. Algorithms are tested on simulated and in vitro data in 2D and 3D contexts. Gain variations across all observed shadows and enhancements are reduced to below 5 dB. The new algorithm is as good as the best alternative on all data sets tested, and is straightforward to implement. We end by discussing further work required to relax the necessary assumptions in order to achieve a similar level of performance on in vivo data.