Novel estimation-registration joint formulation published

A joint formulation for the simultaneous groupwise registration and robust ADC estimation for abdominal diffusion weighted imaging has been published in the international journal Magnetic Resonance Imaging: "Joint Groupwise Registration and ADC Estimation in the Liver using a B-Value Weighted Metric".

Abstract

The purpose of this work is to develop a groupwise elastic multimodal registration algorithm for robust ADC estimation in the liver on multiple breath hold diffusion weighted images. We introduce a joint formulation to simultaneously solve both the registration and the estimation problems. In order to avoid non-reliable transformations and undesirable noise amplification, we have included appropriate smoothness constraints for both problems. Our metric incorporates the ADC estimation residuals, which are inversely weighted according to the signal content in each diffusion weighted image. Results show that the joint formulation provides a statistically significant improvement in the accuracy of the ADC estimates. Reproducibility has also been measured on real data in terms of the distribution of ADC differences obtained from different b-values subsets. The proposed algorithm is able to effectively deal with both the presence of motion and the geometric distortions, increasing accuracy and reproducibility in diffusion parameters estimation.

Highlights

1. A joint registration and estimation procedure for abdominal diffusion weighted imaging is proposed.
2. The proposed groupwise registration metric aims at minimizing the residuals in the estimation.
3. The introduced weighting parameters are design to foster robust ADC estimation. 
4. Joint formulation significantly improves performance with respect to the methods run in isolation.