Intraoperative visualization and assessment of electromagnetic tracking error

Vinyas Harish; Tamas Ungi; Andras Lasso; Andrew MacDonald; Sulaiman Nanji; Gabor Fichtinger

doi:10.1117/12.2082330

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18 March 2015 Intraoperative visualization and assessment of electromagnetic tracking error

Vinyas Harish, Tamas Ungi, Andras Lasso, Andrew MacDonald, Sulaiman Nanji, Gabor Fichtinger

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Proceedings Volume 9415, Medical Imaging 2015: Image-Guided Procedures, Robotic Interventions, and Modeling; 94152H (2015) https://doi.org/10.1117/12.2082330
Event: SPIE Medical Imaging, 2015, Orlando, Florida, United States

Abstract

Electromagnetic tracking allows for increased flexibility in designing image-guided interventions, however it is well understood that electromagnetic tracking is prone to error. Visualization and assessment of the tracking error should take place in the operating room with minimal interference with the clinical procedure. The goal was to achieve this ideal in an open-source software implementation in a plug and play manner, without requiring programming from the user. We use optical tracking as a ground truth. An electromagnetic sensor and optical markers are mounted onto a stylus device, pivot calibrated for both trackers. Electromagnetic tracking error is defined as difference of tool tip position between electromagnetic and optical readings. Multiple measurements are interpolated into the thin-plate B-spline transform visualized in real time using 3D Slicer. All tracked devices are used in a plug and play manner through the open-source SlicerIGT and PLUS extensions of the 3D Slicer platform. Tracking error was measured multiple times to assess reproducibility of the method, both with and without placing ferromagnetic objects in the workspace. Results from exhaustive grid sampling and freehand sampling were similar, indicating that a quick freehand sampling is sufficient to detect unexpected or excessive field distortion in the operating room. The software is available as a plug-in for the 3D Slicer platforms. Results demonstrate potential for visualizing electromagnetic tracking error in real time for intraoperative environments in feasibility clinical trials in image-guided interventions.

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Vinyas Harish, Tamas Ungi, Andras Lasso, Andrew MacDonald, Sulaiman Nanji, and Gabor Fichtinger "Intraoperative visualization and assessment of electromagnetic tracking error", Proc. SPIE 9415, Medical Imaging 2015: Image-Guided Procedures, Robotic Interventions, and Modeling, 94152H (18 March 2015); https://doi.org/10.1117/12.2082330

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