Siemens DICOM Individual Slice Time (Private_1019_1029)

Question

I'm seeing that the individual slice time information from the Private_0019_1029 field of the DICOM header has negative values and sometime only positive values.
I assumed that these times are with respect to the Volume Acquisition time recorded in the header.

Going by that assumption, it would mean that the Acquisition time varies. But upon checking the difference between successive volume acquisition times, I see that it's equal to TR.
So I'm at a loss about what's happening.
I'm trying to look at the raw fMRI data without slice time correction; hence it's necessary to have the individual slice times.

Answer 1

Does the moco series do time shifting in addition to motion correction? (I don't believe it used to, but your experience may show otherwise).

This indicates how their slice timing is measured. Try the computations with the raw and the moco series and see if the times line up. That may give you your answer.

Answer 2

When dealing with private tag, you should really include the Private Vendor ID, in your case the value of tag (0019,0010).

You may also want to have a look at the output of:

gdcmdump --csa input.dcm

This will dump the SIEMENS CSA header directly from the DICOM attribute.