1. An apparatus for registering medical image data representing a tubular structure, comprising: processing circuitry configured to obtain first medical image data representing the tubular structure and second medical image data representing the tubular structure, the first medical image data including a plurality of slices and the second medical image data including a plurality of slices identify the tubular structure in the first medical image data, define in the first medical image data a volumetric region of interest comprising the tubular structure along at least part of the length of the tubular structure, define a subset of the first medical image data corresponding to the volumetric region of interest, match the tubular structure in the subset between the neighboring slices, track a seed point in the neighboring slices based on the matched tubular structure, and perform a registration of the subset of the first medical image data with at least some of the second medical image data based on the tracked seed points, wherein the registration comprises at least one of a rigid registration and an affine registration.