The DWI format expected by the software consists of a couple of different files:
- Listfile: Listfiles are similar to header files in other formats and describe geometric and pyhsical properties of the data. It also contains links to the path files and b-matrix files.
- Path files: The format used by the software expects the files of the data to contain 2D slice images , not 3D volumes or 4D sets of volumes as in other formats. The path file contains the relative paths to every single slice file (with respect to the directory containing the list file - referred to as the Procbase).
- Bmatrix files: This file defines the B-matrix used in diffusion tensor fitting computations. It is a text file containing 6 columns and as many rows as the number of gradients used in the scan.
DIFF_PREP contains import tools for Phillips Par/Rec, GE Dicom, Siemens Dicom, Siemens Mosaic Dicom, and FSL style 4D nifti images. See the Import section of this user manual.
DIFF_PREP registration software uses an additional "structural image" file in addition to the DWI data. As explained in the Software Overview chapter, this ANALYZE or NIFTI format file, is a high resolution anatomical MR image used to describe the coordinate frame for the registered images as well as to compute BO susceptibility induced EPI distortion deformations. The recommended image is a high resolution T2W image with fat saturation, as it has been found to produce the best results for B0 susceptibility induce EPI distortion correction.