Thank you!
I had to do some preprocessing to the EPI data:

3dWarp -oblique2card (linear interpolation)
3dresample (resample to higher resolution)
3dDespike
volreg (align to the base, align to anat, warp to tlrc space)

And it took much time to get the pre-processed EPI files.
The acquisition time of the voxels of the pre-processed EPI files is needed and you say I can do this with the original datasets by using 3dcalc to get the time dataset. So I think I should apply the exact same preprocessing to the time dataset. Otherwise, the locations of the voxels in the pre-processed EPI files and in the time dataset can't match 100%.

Then three new problems come out:
1. Won't the following preprocessing for matching locations changed the time values in this time dataset too much?
I'm afraid that the time values in that dataset will become ridiculous through so much processing.

2. How to apply the exact same preprocessing?
The transformation matrix of volreg had been saved, so I can repeat the exact same transformation to the time dataset. However, the problem is how to do the exact same 3dwarp, 3dresample or 3dDespike?
You say we should do NN interpolation to the time dataset in the process of 3dWarp. But linear interpolations were done to the processed EPI files.
Can't the distinct interpolation method lead to unmatched locations between the voxels in processed EPI files and in the time dataset?

3. How to add timing information to the .Brik files?
The slice timing information seems to be not included in my original EPI dataset because 3dcalc -expr t outputted an all zeros dataset.
I have known the slice timings by reading the raw .IMA files. So how to add these slice timing information to the .Brik files?
I am not sure whether this can work appropriately:

3drefit -TR 2 -Tslices 2.0000    1.9355    1.8710    1.8065    1.7419 ... 0.1935    0.1290    0.0645         0

I will be very appreciated to your replies!
Chen



Edited 6 time(s). Last edit at 10/18/2018 03:58PM by He Chen.