[Freesurfer] Using fieldmap to correct EPI distortions

Hi,

I have a basic question, but the answer can be useful for others as well.

I am doing a customized preprocessing of monkey functional data in FS-FAST v5.3. After motion correction and before functional-anatomical registration, I want to use fieldmap data to correct spatial distortions of EPI data. So:

My fieldmap data: dicom files from a fieldmap scan (there are actually two series of dicom files for that scan)

My EPI data: fmc.nii.gz files in run folders

Now I have three questions:

1) How can I unpack the fieldmap data? An example command ...

2) How can I use FS-FAST's epidewarp.fsl command for my dataset? Again an example command would be very useful.

3) How will the undistorted volumes be used later on in the FS-FAST analysis stream?

Your help would be very much appreciated.

Thanks, Reza