Quantification of Navigator Requirements for Multi-shot Diffusion Weighted Imaging

The ability to use multiple shots in diffusion weighted imaging has enabled acquisitions with higher resolutions and higher SNRs. The methods currently being used to achieve higher resolutions rely on navigator information to correct for mismatches in coherent motion during the diffusion encoding between shots. The resolution of the navigator is a critical factor, too low and the corrections are incomplete, too high and there is a significant time or echo time penalty. This work presents an analysis for determining the resolution requirements for navigation. This work found that using a navigator resolution of 6 mm produces reliable results and allows shorter acquisitions to be used.