Intra-operative volume imaging of the left atrium and pulmonary veins with rotational X-ray angiography.

Complex electrophysiology (EP) procedures, such as catheter-based ablation in the left atrium and pulmonary veins (LAPV) for treatment of atrial fibrillation, require knowledge of heart chamber anatomy. Electroanatomical mapping (EAM) is typically used to define cardiac structures by combining electromagnetic spatial catheter localization with surface models which interpolate the anatomy between EAM point locations in 3D. Recently, the incorporation of pre-operative volumetric CT or MR data sets has allowed for more detailed maps of LAPV anatomy to be used intra-operatively. Preoperative data sets are however a rough guide since they can be acquired several days to weeks prior to EP intervention. Due to positional and physiological changes, the intra-operative cardiac anatomy can be different from that depicted in the pre-operative data. We present a novel application of contrast-enhanced rotational X-ray imaging for CT-like reconstruction of 3D LAPV anatomy during the intervention itself. We perform two selective contrast-enhanced rotational acquisitions and reconstruct CT-like volumes with 3D filtered back projection. Two volumes depicting the left and right portions of the LAPV are registered and fused. The combined data sets are then visualized and segmented intra-procedurally to provide anatomical data and surface models for intervention guidance. Our results from animal and human experiments indicate that the anatomical information from intra-operative CT-like reconstructions compares favorably with pre-acquired CT data and can be of sufficient quality for intra-operative guidance.