Method and apparatus for determining the quality of alignment of a pair of volumes of data of medical images is disclosed. The method for validating the alignment includes selecting one or more points in the first volume and one or more points in the second volume, determining the average distance between the one or more points in the first volume and the one or more points in the second volume, determining a distortion category based on the average distance, determining an average noise level in the first and second volumes, and assigning a Q value indicative of the quality of the alignment based on the distortion category.