Analysis of Catheter-Based Registration with Vessel-Radius Weighting of 3D CT Data to 2D X-ray for Cardiac Catheterisation Procedures in a Phantom Study

X-ray fluoroscopy is routinely used to guide cardiac catheterisations due to its real-time imaging capability and high device visibility, but lacks depth information and poorly visualizes the heart itself. A novel 2D-3D image registration method was developed that can augment 2D fluoroscopy by overlaying 3D CT cardiac images that have excellent soft-tissue information. The method relies on the catheterisation of two vessels during the procedure and globally minimizing a vessel-radius-weighted distance error between the vessel centrelines, segmented from the 3D data, and corresponding catheters reconstructed from biplane X-ray fluoroscopy. Validation of the algorithm was carried out using a glass heart phantom with catheters inserted into combinations of six of its vessels. Results show that registration with the coronary sinus resulted in an average 3D-TRE between 0.55 and 9.1 mm, with the best tested pair being the coronary sinus and descending aorta. The algorithm will be useful for guiding cardiac cauterization procedures and also for co-registration of data for the purposes of biophysical cardiac modelling.