Atlas-assisted tomography: registration of a deformable atlas to compensate for limited-angle cone-beam trajectory

We present a method to improve the quality of cone-beam tomographic images computed from an intra-operative C-arm scan by adding information from an anatomical atlas. Limited range of C-arm view angles leads to reconstruction artifacts and poor anatomical detail. We propose to complete the missing views with simulated projections of a statistical anatomical model, which is deformably registered to match the data in the C-arm images. This paper presents the methods used to create the atlas and to register it with X-ray images. We compare the results of seven leave-one-out simulated hybrid reconstruction tests on a population of 13 subjects, with "ground-truth" CT, a classical short-scan, and a partial-scan reconstruction