Hi Jeongchul
We are currently manually editing the DTI brain masks and will make them public as soon as that is done (probably by June). 

Re field map: No, we did not acquire any field map.

Re DICOM: Not sure why it would be needed, as one easily convert the NRRD data to Nifti (e.g. using DWIConvert/DWIConverter in 3D Slicer). The issue with the DICOM data is that some datasets have incorrect DICOM orientation information, which we corrected.

Re FLIRT:, FLIRT won't be enough for an appropriate correction for the distortions in the diffusion data. The data has significant distortions in the anterior temporal lobe area, which need a non-linear registration (FLIRT is a linear registration tool).

Martin