Hi, Below is my bedpostx_datacheck output. filename /Users/macadmin/data/data.nii.gz data_type INT16 dim1 256 dim2 256 dim3 30 dim4 7 datatype 4 pixdim1 0.5000000000 pixdim2 0.5000000000 pixdim3 2.4000000954 pixdim4 1.0000000000 cal_max 17122.0000 cal_min 0.0000 file_type NIFTI-1+ /Users/macadmin/data/nodif_brain_mask filename /Users/macadmin/data/nodif_brain_mask.nii.gz data_type INT16 dim1 256 dim2 256 dim3 30 dim4 1 datatype 4 pixdim1 0.5000000000 pixdim2 0.5000000000 pixdim3 2.4000000954 pixdim4 1.0000000000 cal_max 0.0000 cal_min 0.0000 file_type NIFTI-1+ num lines in /Users/macadmin/data/bvals 1 num words in /Users/macadmin/data/bvals 7 num lines in /Users/macadmin/data/bvecs 3 num words in /Users/macadmin/data/bvecs 21 I ran 'dtifit'and got outputs which have zero intensity checked by fslstats except dti_V1(V2,V3).nii.gz. Is the intensity of nodif_brain_mask.nii.gz supposed to be [0.00,1.00]? Thanks, Mi Jung