Acoustic Shadowing Aware Robotic Ultrasound: Lighting up the Dark

Abstract

Ultrasound imaging is becoming more prevalent in clinical practice and research. To counteract the drawbacks of high user-dependency and difficult interpretability, ultrasound probes can be attached to robotic arms, enabling an increase in accuracy and repeatability. Currently, robotic ultrasound scans are mainly performed in a perpendicular manner. However, these scans create shadows below high-attenuation structures like bones due to acoustic shadowing, leading to an information loss in the scan. To counteract this and improve the compounding quality of robotic ultrasound scans, we introduce an ultrasound pose optimization method. In this initial work, we focus on the volume coverage of a region of interest and an acoustic shadowing reduction in this volume. Our proposed method is compared against perpendicular scans and random scans. Results show that the volume coverage sweep achieves higher coverage with the trade-off of more performed poses. In addition, the acoustic shadow reduction consistently leads to a higher coverage and confidence of the volumes when applied after a random or perpendicular scan, with a relatively small number of additional poses. Such context-aware volume scanning and path optimization can pave the path to standardized, fully automatic high-quality robotic ultrasound scans without the need for pre-acquired data and systematically reduces the occurrence of acoustic shadows.