Generating of 3D data during neurovascular interventions by using multi-projection imaging

Three-dimensional (3D) vessel data from CTA or MRA are not always available prior to or during endovascular interventional procedures, whereas multiple 2D projection angiograms often are. Therefore, we are developing methods for combining vessel data from multiple 2D angiographic views obtained during interventional procedures to provide 3D vessel data during these procedures. Multiple projection views of vessel trees are obtained. Vessel regions to be analyzed are selected. One of the 2D images is selected as a common image. Initial pairwise imaging geometry relationships are calculated from the gantry information, and 3D vessel centerlines are calculated using pairwise epipolar constraints. The imaging geometries of each of the other views (relative to that of the common image) are then refined by using multidimensional optimization so as to minimize the differences between all pairwise calculated 3D vessel centerlines, and an average centerline is calculated. This final 3D centerline of the carotid vessel is used for calculation of the tortuousity, a quantity related to curvature. The centerlines calculated using the multiple projection approach are in better agreement (1.3 mm) than those calculated using the biplane technique (9.0 mm), and the tortuousity is more continuous along the vessel. Use of multiple projections improves 3D reconstruction of vessel centerlines and tortuousity reliability, which may facilitate image guided interventions.