3D ultrasound imaging has enabled minimally invasive, beating heart intracardiac procedures. However, rapid heart motion poses a serious challenge to the surgeon that is compounded by significant time delays and noise in 3D ultrasound. This paper investigates the concept of using a one-degree-of-freedom motion compensation system to synchronize with tissue motions that may be approximated by 1D motion models. We characterize the motion of the mitral valve annulus and show that it is well approximated by a 1D model. The subsequent development of a motion compensation instrument (MCI) is described, as well as an extended Kalman filter (EKF) that compensates for system delays. The benefits and robustness of motion compensation are tested in user trials under a series of non-ideal tracking conditions. Results indicate that the MCI provides an approximately 50% increase in dexterity and 50% decrease in force when compared with a solid tool, but is sensitive to time delays. We demonstrate that the use of the EKF for delay compensation restores performance, even in situations of high heart rate variability. The resulting system is tested in an in vitro 3D ultrasound-guided servoing task, yielding accurate tracking (1.15 mm root mean square) in the presence of noisy, time-delayed 3D ultrasound measurements.

中文翻译：

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用于心脏跳动的心内手术机器人运动补偿

3D 超声成像使微创、跳动的心脏心内手术成为可能。然而，快速的心脏运动给外科医生带来了严峻的挑战，而且 3D 超声中的显着时间延迟和噪音使情况更加复杂。本文研究了使用单自由度运动补偿系统与可能由一维运动模型近似的组织运动同步的概念。我们描述了二尖瓣环的运动，并表明它可以很好地由一维模型近似。描述了运动补偿仪器 (MCI) 以及补偿系统延迟的扩展卡尔曼滤波器 (EKF) 的后续开发。在一系列非理想跟踪条件下的用户试验中测试了运动补偿的好处和稳健性。结果表明，与实体工具相比，MCI 的灵活性提高了大约 50%，力量降低了 50%，但对时间延迟很敏感。我们证明使用 EKF 进行延迟补偿可以恢复性能，即使在心率变异性较高的情况下也是如此。由此产生的系统在体外 3D 超声引导伺服任务中进行了测试，在存在噪声、延时 3D 超声测量的情况下产生准确的跟踪（1.15 毫米均方根）。