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Hi, I'm currently working on a DTI dataset. After converting the par/rec files to .nii using dcm2nii, I run my preprocessing script that performs BET and eddy (I did not collect two PE encoding directions to be able to use topup). I want to check how much each subject moved, and I do so by looking at the data.nii.gz.eddy_restricted_movement_rms. I collected 32 diffusion-weighted volumes (b = 1000), and then I collected the b0 volume last. So, I have 33 volumes, and the 33rd/last one is the b0 volume. The .nii.gz input to eddy's --main contained these 33 volumes in this order. The resulting data.nii.gz.eddy_restricted_movement_rms output looks strange: 1.791700783e-18 0 0.06516983012 0.06516983012 0.03727414979 0.03311060197 0.05048822764 0.05300074095 0.08412833163 0.05433180986 0.1060893866 0.03267023346 0.08129064612 0.07338530022 0.06546124531 0.05200651598 0.07587254987 0.05894195918 0.02191728514 0.07905276209 0.05784966012 0.06064533619 0.1360513561 0.1078217652 0.1734909361 0.04868022819 0.1791658781 0.05019219236 0.07514948591 0.1497840628 0.07441728076 0.1077611043 0.07441728076 0 0.1092357573 0.07722524328 0.1194563162 0.0316786453 0.1314062274 0.09104526627 0.1313261419 0.02706846189 0.1241843559 0.08217575252 0.1545527423 0.04819860736 0.1495629422 0.04479223168 0.1448678673 0.0297820626 0.1734707279 0.04188719639 0.1614983891 0.03058816812 0.1960288622 0.04160574513 0.1712803419 0.1007587351 0.1568447585 0.08210929242 0.2193606603 0.07472747724 0.2294818291 0.03428336793 0 0.2294818291 My understanding is that the values in the first column refer to the corresponding volume's displacement relative to the first volume. And the values in the second column refer to the corresponding volume's displacement relative to the previous volume. I also recognize that eddy automatically assumes that the movement between the b0 volume and the first volume is zero. However, I wanted to avoid this assumption, so I used the --dont_peas flag (https://fsl.fmrib.ox.ac.uk/fsl/fslwiki/eddy/UsersGuide/#A--dont_peas) when using eddy. Nevertheless, I still get a 0 for the last value in the first column, which means that eddy is interpreting that the b0 volume had zero displacement relative to the first volume (which seems impossible). Additionally, the second-to-last value in the first column is identical to the last value in the second column - again, I'm not sure why. And, there's another zero in the middle of the second column; I find it hard to believe that there is absolutely 0 movement between any volumes. I'd hugely appreciate any help and explanation! Thank you very much in advance for your time and help. Best, Ryan