One approach to assessing the results of NRR is to create a set of test images by taking original images and applying known spatial deformations. Evaluation involves comparing the deformation fields recovered by NRR to those known to have been applied [14,15]. This approach can be used to test a given NRR method 'off-line', but cannot be used to evaluate the results when the method is applied to real data as part of a registration-based analysis.
An alternative approach involves measuring the coincidence of anatomical annotations following registration. Variants of this approach include measuring the mis-registration of anatomical landmarks [8,10], and the overlap between anatomically equivalent regions obtained using manual or semi-automatic segmentation [10,14]. These methods are of general application, but are labour-intensive and error prone.