2D-3D vascular registration between digital subtraction angiographic (DSA) and magnetic resonance angiographic (MRA) images

In this paper, we propose a 2D-3D vascular registration algorithm based on an efficient rendering method for generating 2D projected images from a segmented 3D MRA volume. At the preprocessing stage, vessels are segmented and represented by a number of spheres with centers on the skeleton points of the vessels and radii equal to the distance from the skeleton points to their closest boundary. To generate projected images for 2D-3D registration, instead of using the conventional ray-casting technique, the spheres are projected to the projection plane. The discrepancy between the projected image and the reference DSA image is measured by the sum of squared differences. Experimental results show that our method is computationally efficient. Moreover, based on manually selected markers, it is shown that the accuracies of our proposed method and the conventional ray-casting based registration method are comparable.