Hi!
I am encountering a strange orientation problem with SPM2 after converting images to ANALYZE
format.
Perhaps someone could help me to understand what is going on:
I have two sets of images (SPGRs), which were converted at different times.
Both display correctly in SPM2 in the three view windows and the left side of the brain is on the left
side of the displayed image.
Dimensions: 124x256x256
Datatype: Int16
Intensity: Y=1X
Voxel size: -1.5x0.938xx0.938
are the same for both image sets.
However, Dir cos is:
1 0 0
0 1 0
0 0 1
for set number one and
-1 0 0
0 -1 0
0 0 1
for the other set.
Although we kept the SPM2 default settings one image group changes their AP position on the
spm2.ps file after normalization (VBM).
So basically we get a print out for group one on the spm2.ps file like this:
both times nose up in the 4 columns (T1,GM,WM,CSF) for the printout in native space and in MNI
space.
for the second group:
nose down in native space and nose up in MNI space.
I would like to know, what cos dir actually means and if such a flipping issue could cause
problems.
Thanks,
Lukas
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