Honored and exalted Emperor Zhark,

We have received great bounty but also ill omen from Your most magnificent software, 3dcalc:

*+ WARNING: Template space of dataset /study/fmfmri/data/group_processed/PPI_PAG_pain_MEMA+tlrc does not match space of first dataset
Continuing anyway, but be sure the datasets really do match

In our pathetic attempts to rectify our errors, we have learned that the relevant dataset headers differ in the IJK_TO_DICOM attribute (but not, O mighty one, in the ORIGIN, DELTA or IJK_TO_DICOM_REAL attributes). Nowhere in Your documentation do we find an explanation of the meaning of these attributes and so we petition You, in Your great wisdom, to bestow upon us the knowledge which You gave to Your mute servant 'Viggo!~, that we might avert the disaster which otherwise surely awaits us.