Catheter tracking in asynchronous biplane fluoroscopy images by 3D B-snakes

Abstract

Minimally invasive catheter ablation procedures are guided by biplane fluoroscopy images visualising the interventional scene from two different orientations. However, these images do not provide direct access to their inherent spatial information. A three-dimensional reconstruction and visualisation of the catheters from such projections has the potential to support quick and precise catheter navigation. It enhances the perception of the interventional situation and provides means of three-dimensional catheter pose documentation. In this contribution we develop an algorithm for tracking the three-dimensional pose of electro-physiological catheters in biplane fluoroscopy images. It is based on the B-Snake algorithm which had to be adapted to the biplane and in particular the asynchronous image acquisition situation. A three-dimensional B-spline curve is transformed so that its projections are consistent with the catheter path enhancing feature images, while the information from the missing image caused by the asynchronous acquisition is interpolated from its sequence neighbours. In order to analyse the three-dimensional precision, virtual images were created from patient data sets and threedimensional ground truth catheter paths. The evaluation of the three-dimensional catheter pose reconstruction by means of our algorithm on 33 of such virtual image sets indicated a mean catheter pose error of 1.26 mm and a mean tip deviation of 3.28 mm. The tracking capability of the algorithm was evaluated on 10 patient data sets. In 94 % of all images our algorithm followed the catheter projections.