Groupwise Non-Rigid Registration On Multiparametric Abdominal Dwi Acquisitions For Robust Adc Estimation: Comparison With Pairwise Approaches And Different Multimodal Metrics

Abstract

Registration of diffusion weighted datasets remains a challenging task in the process of quantifying diffusion indexes. Respi- ratory and cardiac motion, as well as echo-planar characteristic geometric distortions, may greatly limit accuracy on parameter estimation, specially for the liver. This work proposes a methodology for the non-rigid registration of multiparametric abdomi- nal diffusion weighted imaging by using different well-known metrics under the groupwise paradigm. A three-stage validation of the methodology is carried out on a computational diffusion phantom, a watery solution phantom and a set of voluntary patients. Diffusion estimation accuracy has been directly calculated on the computational phantom and indirectly by means of a residual analysis on the real data. On the other hand, effectiveness in distortion correction has been measured on the phan- tom. Results have shown statistical significant improvements compared to pairwise registration being able to cope with elastic deformations.