Improved 3D reconstruction of pacemaker leads

Recently, serious health risks to recipients of pacemakers due to the failure and fracture of structural pacemaker components has placed an emphasis on the need for methods of evaluating pacemaker components in vivo. In order to facilitate these evaluations, we have developed methods for determination of the in-vivo 3D positions of pacemaker leads during the entire heart cycle. Sequences of biplane images of patients with pacemakers were obtained at 30 frames/sec for each projection. The sequences usually included at least two heart cycles. After patient imaging, biplane images of a calibration object were obtained from which the biplane imaging geometry was determined. The centerlines of the leads were indicated manually for all acquired images. These lead data were interpolated temporally so that the temporal non-synchronicity of the image acquisition was overcome. Epipolar lines, generated from the calculated geometry, were used to adjust the temporally interpolated data based on known consistencies of simultaneously acquired images. The 3D positions of the leads were then calculated using the calculated geometry and point correspondences between leads in simultaneous projections using an epipolar technique. Calculated results indicate that an accurate estimate of the shapes and positions of pacemaker leads throughout the heart cycle can be determined, providing a reliable basis for the needed stress analysis.