I am relatively new to DWI data, but am familiar with T1/2 anatomical data using slicer, spm, and fsl. I have just converted animal (pig) DWI DICOMs into NifTI format using dcm2niix, which also produced a bval, bvec, and JSON files for me. I am wanting to preprocess this DWI data to correct for distortions where possible before I brain mask the data.
My question is this - is there a way to tell just by looking at the DWI dataset (DICOM or NifTI) if the data was acquired as a single-direction encoding dataset or multi-direction? There are 186 DICOM images per DWI dataset, and 46 images per ADC, FA, COLFA, and TRACE datasets. There is 1 image in a TENSOR folder. The images were acquired on a Siemens 3T Trio machine. In one of the animals there are two datasets, but I believe one is axial and one is sagittal slices.
My sense is that since there is no obvious paired dataset, I only have a single-direction encoding dataset. Can you tell the direction of encoding just by looking at the image on fsleyes? For me the distortion appears to be in the ap direction, so I am thinking of running dwifslpreproc input.nii output.nii -rpe_none -pe_dir ap -fslgrad bvec bval.
Any input would be much appreciated!