3dQwarp touches data obliqueness?

AFNI Message Board
1

Hi AFNI-experts,

I’m trying to create a warp field between two EPI’s scanned in opposite directions, using the plusminus procedure of 3dQwarp. However, I have noticed that it always forces the axes tilt to be plumb, and interpolating data to do so. I am trying to make sure that this does NOT happen, as I am building a pipeline where my functional data is touched as little as possible. Is there a way to tell 3dQwarp to leave the obliqueness of my data alone? If not, is there an alternate way of computing the warp field that serves my purposes?

Thanks in advance,
Martijn.

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All the spatially transforming programs remove the obliquity of the data, but maybe that one shouldn’t, or should only match the grid and obliquity of the base dataset. In any case, to restore the oblique information, you can do something like this:

3drefit -atrcopy IJK_TO_DICOM_REAL original_dset warped_dset

To use this, the grid has to be exactly the same size, i.e. the number of rows, columns and slices are the same for both the warp and original datasets.