1. A method for registering images obtained in a multi-modal medical imaging system, the method comprising: setting a first image as a target image and setting a second image as an object image, wherein the first and second images are obtained from first and second imaging modalities, respectively; segmenting the object image into one or more anatomic segments, each segment associated with a respective anatomic class; assigning at least one attribute to at least one of the anatomic segments based on the anatomic class corresponding to said at least one anatomic segment; and using a computer of the multi-modal medical imaging system, performing a registration with the object image and the target image, wherein the registration is constrained by the assigned at least one attribute.