1. A method, comprising: obtaining projection data from a scan of a moving structure of interest; reconstructing the projection data, generating first image data; identifying a sub-set of the projection data; reconstructing the sub-set of the projection data, generating second image data; identifying a region in the first image data in which the moving structure of interest is located; and identifying a location of the moving structure of interest in the second image data based on the identified region in the first image data.