Dreidimensionale Rekonstruktion und Verfolgung von Elektrophysiologiekathetern aus asynchronen biplanaren Fluoroskopiebildsequenzen

Abstract

The presented work provides a contribution to the field of computer-assisted catheter reconstruction and tracking on fluoroscopy sequences. During a minimally invasive catheter ablation intervention, various catheters are navigated inside the heart under display of two-dimensional X-ray image sequences. The physician is faced with the challenge of properly reconstructing the spatial position of the catheters in his mind. If the geometry of the fluoroscopy system and the positions of the catheter projections in the two image planes are known, the automatic determination of the spatial position of the catheter becomes possible by triangulation. This results in applications such as the direct 3D representation of the procedure and the measurement of the cardiac motion. Overall, the support of the catheter ablation intervention in this form has the potential to simplify, speed up, improve and assure the quality of the procedure. In the presented work, two novel approaches are being investigated for this purpose. They allow a temporal tracking and spatial reconstruction of the catheter using image processing algorithms. The first approach is based on the detection of the catheter tip in the image using a template-matching method and the temporal tracking of its three-dimensional reconstruction by a model-based state filtering method. The special image acquisition situation is dealt with by an implicit triangulation in the state filter. The temporal tracking and spatial reconstruction of a longer course of the catheter body is solved in the second approach by an iterative curve deformation method. In addition, a novel approach to simplify the initialization of the tracking algorithms is presented based on the curve deformation algorithm. The evaluation of the algorithms on a collection of several patient records as well as on simulations show an acceptable accuracy of reconstruction and robustness of the catheter tracking for clinical practise.