Efficient Aberration Correction via Optimal Bulk Speed of Sound Compensation
Diagnostic ultrasound is a versatile and practical tool in the abdomen, and is particularly vital toward the detection and mitigation of early-stage non-alcoholic fatty liver disease (NAFLD). However, its performance in those with obesity -- who are at increased risk for NAFLD -- is degraded due to distortions of the ultrasound as it traverses thicker, acoustically heterogeneous body walls (aberration). Extant aberration correction methods for ultrasound are typically computationally intensive, as they require analysis of the much larger time series dataset, while optimizations based on image quality have not been analyzed or tested in the case of abdominal aberration. Herein, we assess analytically the capability of a single, optimal bulk speed of sound correction in receive beamforming to correct aberration, and improve the resulting images. Additionally, we propose an objective metric on the beamformed image to identify this speed of sound. We find that a bulk correction may approximate the aberration profile for layers or relevant thicknesses (1 to 3 cm) and speeds of sound (1400 to 1500 m/s). Additionally, through in vitro experiments, we show significant improvement in resolution (average point target width reduced by 60 % and improved boundary delineation in vivo with bulk speed of sound correction determined automatically from the beamformed images Together, our results demonstrate the utility of simple, efficient bulk speed of sound correction to improve the quality of diagnostic liver images.
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