Closing the gap: From planning to intervention in cardiology

It is likely that in the near future the diagnostic of coronary arteries will be done using non-invasive computed tomography angiography and that only the intervention, if necessary, will be carried out using invasive techniques. Pre-interventional gathered CTA data can be used to carry out an automated quantitative analysis of the arteries, which can provide complementary information during a cardiac catheterization when only coronary angiograms are available. We propose an anatomical landmark-based rigid 3D/2D registration algorithm which enables the fusion of both modalities. It has to solve for six transformation parameters (three rotation and three translation parameters). An exhaustive search in a six dimensional search space is usually computationally very expensive and algorithms using optimization strategies can get lost in local minima. We propose a method based on centroids to reduce search space from six to four dimensions and use information stored in modern C-Arm devices to further reduce the search space. With our method registration errors of < 2 mm are feasible. Execution times of < 1 sec. can be reached on a QuadCore CPU.