Catheter based calibration for augmented reality guidance of cardiac thermo-ablation procedures

Introducing a patient specific model in an augmented reality environment for cardiac thermo-ablation procedures, requires a calibration strategy that is sufficiently accurate and easily applicable without compromising the image quality that is conventionally expected. We present a two-step calibration method and registration strategy which can satisfy these requirements. Relying only on catheter electrode correspondences and the knowledge of the rotation between the fluoroscopes, the method retrieves both the parameters of fluoroscopic devices, including non-linear distortion effects, and the electrode positions. Registration can subsequently be performed by visually matching the pre-operative model to the fluoroscopic images inside the augmented reality framework. Simulations under real life conditions and validation on real images show an accuracy of 5 pixels which is equivalent to <2 mm in world coordinates. Validation experiments on real images and with calibration jig as gold standard show a mean reconstruction accuracy of 1,33 mm resulting and a mean image plane error of 5.48 pixels.