Hello,
This is not directly an afni question but I was hoping you could help me. I read through your list, searching for "DICOM" and it seems that you have taken time to understand the header. I don't know anyone else who knows this stuff...so, hopefully you can help me with this orientation question: is it possible to determine the direction in which slices were acquired from the DICOM header?
There is a field in the header, (0020,0037) which specifies the orientation of the slice. So if the images were acquired sagittaly, and this field reads:
0\1\0\0\0\-1, that would translate into AS orientation for the slice. This is all under the assumption that the default DICOM orientation, patient based is RAI. But what about the order of slices. In this particular example, are the slices R-L or L-R? I looked each field in the header, and tried to look for the information in the DICOM documentation (arghhhh) but I could not find anything. My though was that, if the orientation of the axis is always right-hand, then I could find the orientation of the third by vector product of the other two. But is that assumption correct? In the previos case that would mean that the third vector would be -1, which would be -x, or L-R.
(Is it possible, that with all that info in the header, we need to rememeber in which order we prescribed the slices?Hmmm)
I tried opening these images with to3d, and to3d correctly recognized the AS orientation of the sag slices. However, the third axis was specified as R-L. How does afni determine the order of slices in case of a DICOM file?
Thank you very much!
Zrinka