A REGISTRATION AND INTERPOLATION PROCEDURE FOR SUBVOXEL MATCHING OF SERIALLY ACQUIRED MR-IMAGES

Objective: Methods for automatically registering and reslicing MR imag es using an interpolation function that matches the structure of the i mage data are described. Materials and Methods: Phantom and human brai n images were matched by rigid body rotations and translations in two and three dimensions using a least-squares optimization procedure. Sub voxel image shifts were produced with linear or sine interpolation. Re sults: The use of sine interpolation ensured that the repositioned ima ges were faithful to the original data and enabled quantitative intens ity comparisons to be made. In humans, image segmentation was vital to avoid extraneous soft tissue changes producing systematic errors in r egistration. Conclusion: The sine-based interpolation technique enable d serially acquired MR images to be positionally matched to subvoxel a ccuracy so that small changes in the brain could be distinguished from effects due to misregistration.