Evaluation of polynomial image deformation using anatomical landmarks for matching of 3D-abdominal MR-images and for atlas construction

While a variety of different deformation algorithms have been implemented for matching of skull, few attempts in matching areas in abdomen have been reported. In this study the authors evaluate the usability of first and second order polynomial 3D-warping for this purpose. They match abdominal MR-images from different individuals using manually picked anatomical landmarks. Generation of transformation coefficients was done through a linear regression technique that employs a least square fit using the reference landmarks. The landmarks were picked in a predefined order, well spread over the entire data set, by a radiologist. The image resampling was done using linear interpolation and the evaluation was performed visually as well as by calculating the cross correlation and the normalized least squared error between the original image and the transformed image. The authors' preliminary results reveal that the second order polynomial transformation using landmarks is a robust and efficient method. It is also superior to the second order one, for image deformation in the abdominal region and it may be used in atlas generation as well as in multimodality image co-registration and fusion.