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Hi, I am trying to use the fugue function to correct off resonance effect of an EPI image using the following line: fugue -i epi_magnitude --dwell=dwelltime --loadfmap=fieldmap -u result I have several questions regarding this line: 1. Does the epi_magnitude image need to have the same matrix size as the field map? That is, if my fieldmap is 256 x 256 and my epi_magnitude is 64 x 64, does fugue downsample my fieldmap to 64x64 for me or I need to do that myself? 2. The fieldmap is computed from two phase images of fGRE(256 x 256) with a TE shift and unwarped using prelude. The matrix size of the epi image is 64 x 64, both were acquired with miscalibrated xy shim with a water phantom. The epi image is clearly distorted and however when i run this line, I didn't see any corrections in the result image. Am I using fugue correctly as it is intended? Since the data is acquired with a phantom and there is no motion involved, I have skipped steps of coregistration and etc. Any help or suggestions would be great! Much appreciated your help!