Scanning Beam Digital X-ray (SBDX) is a low-dose inverse geometry fluoroscopic system for cardiac interventional procedures. The system performs x-ray tomosynthesis at multiple planes in each frame period and combines the tomosynthetic images into a projection-like composite image for fluoroscopic display. We present a novel method of stereoscopic imaging using SBDX, in which two slightly offset projection-like images are reconstructed from the same scan data by utilizing raw data from two different detector regions. To confirm the accuracy of the 3D information contained in the stereoscopic projections, a phantom of known geometry containing high contrast steel spheres was imaged, and the spheres were localized in 3D using a previously described stereoscopic localization method. After registering the localized spheres to the phantom geometry, the 3D residual RMS errors were between 0.81 and 1.93 mm, depending on the stereoscopic geometry. To demonstrate visualization capabilities, a cardiac RF ablation catheter was imaged with the tip oriented towards the detector. When viewed as a stereoscopic red/cyan anaglyph, the true orientation (towards vs. away) could be resolved, whereas the device orientation was ambiguous in conventional 2D projection images. This stereoscopic imaging method could be implemented in real time to provide live 3D visualization and device guidance for cardiovascular interventions using a single gantry and data acquired through normal, low-dose SBDX imaging.
Keywords: cardiac interventional procedures; inverse geometry; stereoscopic x-ray fluoroscopy.