 |
 |
Dear Christopher, SPM indeed does not have a notion to "deoblique" any data. Except for time series statistics, most image manipulation operations work in "world space", taking arbitrary locations of image slices (and most of the time even arbitrary image dimensions an voxel sizes) into account. If you run "Realign: Estimate" or "Coregister: Estimate" on your data, SPM will only update the spatial transformation from voxel to "world space" without touching any voxel data. Your normalisation parameters will map back and forth between "coregistered subject space" and "MNI space". Data will always be written in oblique slices, but will be in register with any data that is in the target space of the normalisation. If you transform data from MNI space back to "coregistered subject space" and need to have that in exactly the same orientation and voxel size as the original data, an additional "Realign: Reslice" could help. Select a single image that has the required orientation and voxel size (e.g. the first of your coregistered original EPIs) and all "reverse-normalised" images you want to reslice. Set the output option to "Images 2..n" (your first image in the list is used as reference only). You may have to experiment a bit with the resolution of the images created during spatial normalisation from MNI to subject space, but otherwise it should not be necessary to reapply any coregistration. Hope this helps Volkmar