Lung lobar slippage assessed with the aid of image registration.

We present a registration algorithm that can handle the discontinuity of deformation with an ultimate goal to investigate how pulmonary lobes deform to accommodate chest wall shape changes. We first show that discontinuities can exist in both normal and tangent directions. Such discontinuities are accounted for by a spatially varying diffusive regularization which restricts smoothing inside objects. Meanwhile, a distance term is combined with the sum of squared intensity differences (SSD) to explicitly match corresponding interfaces and intensity patterns. The capability of this new method is demonstrated using two-dimensional (2-D) synthetic examples with complete or incomplete "fissures" and three-dimensional (3-D) computed tomography (CT) lung datasets.