In vitro evaluation of stereoscopic liver surface reconstruction.

Abstract

IntroductionTracking abdominal motion of organs is an important factor in image-guided navigation systems. The paper presents the evaluation methodology of a practical approach to measure liver motion, both respiratory and laparoscopic, with a tool guided in the operating room. AimEvaluation of the methodology of a practical approach to measure liver motion, both respiratory and laparoscopic, with a tool guided in the operating room. Material and methodsThe presented evaluation method is based on standard operating room equipment, i.e. laparoscopic cameras. We decided to use two rigid cameras to gain stereo in order to reconstruct characteristic points by triangulation. Our research aim was to survey the impact of three parameters on reconstruction accuracy: the number of calibration points, the imprecision of camera assembly, and the difference in resolution of images. ResultsThree calibration chessboard configurations were tested. The reconstructed landmark positions and residual mean square errors were presented in three phantom poses: the reference position, translated position and rotated position. ConclusionsThe presented approach is a development of the previous work. Our research proved the importance of a rigid stereo camera system and the use of high definition image resolution for both stages, namely calibration and reconstruction.

Time-Of-Flight Camera, Optical Tracker and Computed Tomography in Pairwise Data Registration

“…The common problem of fiducial markers attachment is its physically invasive character, always causing some level of danger during the treatment. In the past years those two limitations have been studied and other propositions have been formulated, mostly for the more demanding soft tissue surgery [ 18 , 19 ]. The noninvasiveness requirement is being overcome by the surface matching techniques replacing marker matching approaches [ 20 ].…”

Preparing the anatomical model for ablation of unresectable liver tumor.

“…The main advantage of IGI systems is presenting a model of the operation field including tumors and positions of surgical tools on an extra medical monitor, which shortens the intervention and improve safety in general [ 7 ] and for liver ablation [ 8 ]. Tracking points of the liver is a complex process, whose accuracy is also influenced by parameters of the stereo camera, which was set up by two laparoscopic monocular cameras and the calibration procedure [ 9 ]. Previous work has shown that mobility of the individual points of the liver reaches millimeters due to respiratory motion or even centimeters under pressure of laparoscopic tools [ 10 ].…”