Robust Multi-Shot Diffusion Weighted Imaging of the Abdomen with Region-Based Shot Rejection

Motivation: To improve the motion robustness of multi-shot DWI in the abdomen and reduce signal dropouts and ADC overestimation caused by unresolved shot-to-shot phase. Goal(s): Demonstrate that region-based weighting of different shots improves diffusion contrast in rapidly moving abdominal organs. Approach: Shot rejection was evaluated in the pancreas. Multiple shot rejection formulations were tested, and compared using conventional monopolar, and motion-compensated diffusion encodings. Results: Shot rejection allows conventional monopolar encoding to achieve diffusion weighting and ADCs similar to the motion-compensated encoding in the pancreas. The reconstruction is linear, requires no modifications to the sequence, and is applicable to many encoding trajectories. Impact: Shot rejection may improve the consistency and robustness of multi-shot abdominal DWI in the clinic, as well as its ability to differentiate pathologies. This will improve repeatability of DWI studies of rapidly moving organs, such as the pancreas and heart.