Robust ultrasound probe tracking: initial clinical experiences during robot-assisted partial nephrectomy

Abstract

PURPOSE:In order to assist in the identification of renal vasculature and tumour boundaries in robot-assisted partial nephrectomy, robust ultrasound probe calibration and tracking methods are introduced. Contemporaneous image guidance during these crucial stages of the procedure should ultimately lead to improved safety and quality of outcome for the patient, through reduced positive margin rates, segmental clamping, shorter ischaemic times and nephron-sparing resection. METHODS:Small KeyDot markers with circular dot patterns are attached to a miniature pick-up ultrasound probe. Generic probe calibration is superseded by a more robust scheme based on a sequence of physical transducer measurements. Motion prediction combined with a reduced region-of-interest in the endoscopic video feed facilitate real-time tracking and registration performance at full HD resolutions. RESULTS:Quantitative analysis confirms that circular dot patterns result in an improved translational and rotational working envelope, in comparison to the previous chessboard pattern implementation. Furthermore, increased robustness is observed with respect to prevailing illumination levels, and out-of-focus images due to relatively small endoscopic depths of field.CONCLUSION: Circular dot patterns should be employed in this context as they result in improved performance and robustness. This facilitates clinical usage and interpretation of the combined video and ultrasound overlay. The efficacy of the overall system is demonstrated in the first human clinical case.

Real-time surgical tool tracking and pose estimation using a hybrid cylindrical marker

“…As reported in [5], the detection rate of a circular-dot feature is higher than of a chessboard feature. In order to evaluate the detection rate of the proposed marker, which consists of both circular dot and chessboard vertices, we compared with two previous marker designs with one containing only chessboard vertices [6] and the other one containing only circular-dot [5].…”

“…In order to evaluate the detection rate of the proposed marker, which consists of both circular dot and chessboard vertices, we compared with two previous marker designs with one containing only chessboard vertices [6] and the other one containing only circular-dot [5]. The proposed hybrid and the chessboard only markers were placed on the 10-mm-diameter cylindrical rigid body.…”

“…The introduction of additional tracking devices into the theatre would not only occupy the valuable space in the operating field, but also suffer from intrinsic limitations of these tracking devices such as ferromagnetic interference and line-of-sight issues. Previous methods have extracted 2D locations of a planar [5] or cylindrical [6] marker that is rigidly attached to the probe. In Table 1, a list of marker-based tracking methods for intraoperative ultrasound probes is presented.…”

GIFT-Grab: Real-time C++ and Python multi-channel video capture, processing and encoding API

“…Other examples include real-time stereo reconstruction [48] and probe tracking [49] in robotic surgery, surveillance endoscopies [50], real-time panorama image synthesis [51], vehicle surveillance [52] and content-based video identification [53]. GIFT-Grab allows real-time video processing applications to connect to external devices and to encode video data from these devices.…”

Laparoscopic stereoscopic augmented reality: toward a clinically viable electromagnetic tracking solution

“…This registration can be achieved through different approaches. A promising but still evolving approach is the vision-based approach, 3,5,6,12,13 which uses computer vision techniques to track in real-time intrinsic landmarks and/or userintroduced patterns within the field of view. Although no external tracking hardware is needed, the vision-based approach needs further research and development to achieve the accuracy and robustness needed for reliable clinical use.…”