Free-form image registration of human cochlear μCT data using skeleton similarity as anatomical prior

We create simple parametric centerline descriptions for human µCT cochlears.We regularize intensity-based image registration with centerline correspondences.We show that a skeleton can act as an useful global anatomical registration prior. Better understanding of the anatomical variability of the human cochlear is important for the design and function of Cochlear Implants. Proper non-rigid alignment of high-resolution cochlear µCT data is a challenge for the typical cubic B-spline registration model. In this paper we study one way of incorporating skeleton-based similarity as an anatomical registration prior. We extract a centerline skeleton of the cochlear spiral, and generate corresponding parametric pseudo-landmarks between samples. These correspondences are included in the cost function of a typical cubic B-spline registration model to provide a more global guidance of the alignment. The resulting registrations are evaluated using different metrics for accuracy and model behavior, and compared to the results of a registration without the prior.