Medical ultrasound (US) imaging is a frontline tool for the diagnosis of kidney diseases. However, traditional freehand imaging procedure suffers from inconsistent, operator-dependent outcomes, lack of 3D localization information, and risks of work-related musculoskeletal disorders. While robotic ultrasound (RUS) systems offer the potential for standardized, operator-independent 3D kidney data acquisition, the existing scanning methods lack the ability to determine the optimal imaging window for efficient imaging. As a result, the scan is often blindly performed with excessive probe footprint, which frequently leads to acoustic shadowing and incomplete organ coverage. Consequently, there is a critical need for a spatially efficient imaging technique that can maximize the kidney coverage through minimum probe footprint. Here, we propose an autonomous workflow to achieve efficient kidney imaging via template-guided optimal pivoting. The system first performs an explorative imaging to generate partial observations of the kidney. This data is then registered to a kidney template to estimate the organ pose. With the kidney localized, the robot executes a fixed-point pivoting sweep where the imaging plane is aligned with the kidney long axis to minimize the probe translation. The proposed method was validated in simulation and in-vivo. Simulation results indicate that a 60% exploration ratio provides optimal balance between kidney localization accuracy and scanning efficiency. In-vivo evaluation on two male subjects demonstrates a kidney localization accuracy up to 7.36 mm and 13.84 degrees. Moreover, the optimal pivoting approach shortened the probe footprint by around 75 mm when compared with the baselines. These results valid our approach of leveraging anatomical templates to align the probe optimally for volumetric sweep.

翻译：医学超声成像技术是肾脏疾病诊断的一线工具。然而，传统自由手扫查方式存在成像结果不一致、依赖操作者经验、缺乏三维定位信息以及易引发职业性肌肉骨骼损伤等问题。虽然机器人超声系统为实现标准化、非依赖操作者的三维肾脏数据采集提供了可能，但现有扫描方法无法确定高效成像所需的最佳声窗。这导致扫描过程常盲目进行且探头移动轨迹过大，易产生声影伪影并导致器官覆盖不全。因此，亟需一种空间高效的成像技术，能够通过最小化探头移动轨迹实现最大化的肾脏覆盖。本研究提出一种基于模板引导最优枢轴扫描的自主工作流程以实现高效肾脏成像。该系统首先执行探索性成像以获取肾脏部分观测数据，随后通过配准至肾脏模板来估计器官姿态。在完成肾脏定位后，机器人执行定点枢轴扫描，使成像平面与肾脏长轴对齐以最小化探头平移。所提方法在仿真和活体实验中均得到验证。仿真结果表明，60%的探索比率能在肾脏定位精度与扫描效率之间达到最优平衡。对两名男性受试者的活体评估显示，肾脏定位精度达到7.36毫米和13.84度。此外，与基线方法相比，最优枢轴扫描方法将探头移动轨迹缩短约75毫米。这些结果验证了利用解剖学模板优化探头位姿以实现容积扫描的有效性。