Hi all, I am trying to mask one image with another using fslmaths. I am getting the error: WARNING:: Inconsistent orientations for individual images in pipeline! Will use voxel-based orientation which is probably incorrect - *PLEASE CHECK*! I suspect that it is due to the header files being slightly different (attached to the end of this mail). The two files were created in two different programmes (FSL and Freesurfer) and the header information is very slightly different for each file. Can I safely ignore this warning? The results that I am seeing are as expected and it is not crucial that the masking be perfect but I just get very wary when I start seeing error messages. Regards, Claude HEADER 1: filename _03DN_lh_G_and_S_cingul-Ant.nii.gz sizeof_hdr 348 data_type INT32 dim0 3 dim1 128 dim2 128 dim3 60 dim4 1 dim5 1 dim6 1 dim7 1 vox_units mm time_units s datatype 8 nbyper 4 bitpix 32 pixdim0 0.0000000000 pixdim1 1.8750000000 pixdim2 1.8750000000 pixdim3 2.0999999046 pixdim4 0.0000000000 pixdim5 1.0000000000 pixdim6 1.0000000000 pixdim7 1.0000000000 vox_offset 352 cal_max 0.0000 cal_min 0.0000 scl_slope 0.000000 scl_inter 0.000000 phase_dim 0 freq_dim 0 slice_dim 0 slice_name Unknown slice_code 0 slice_start 0 slice_end 0 slice_duration 0.000000 time_offset 0.000000 intent Unknown intent_code 0 intent_name intent_p1 0.000000 intent_p2 0.000000 intent_p3 0.000000 qform_name Scanner Anat qform_code 1 qto_xyz:1 -1.875000 0.000664 0.000000 119.092148 qto_xyz:2 0.000664 1.875000 0.000453 -119.117523 qto_xyz:3 -0.000000 -0.000405 2.100000 -61.385921 qto_xyz:4 0.000000 0.000000 0.000000 1.000000 qform_xorient Right-to-Left qform_yorient Posterior-to-Anterior qform_zorient Inferior-to-Superior sform_name Scanner Anat sform_code 1 sto_xyz:1 -1.875000 0.000664 0.000000 119.092148 sto_xyz:2 0.000664 1.875000 0.000453 -119.117523 sto_xyz:3 0.000000 -0.000405 2.100000 -61.385921 sto_xyz:4 0.000000 0.000000 0.000000 1.000000 sform_xorient Right-to-Left sform_yorient Posterior-to-Anterior sform_zorient Inferior-to-Superior file_type NIFTI-1+ file_code 1 descrip FreeSurfer Feb 26 2013 aux_file HEADER 2: filename gwi.nii sizeof_hdr 348 data_type FLOAT32 dim0 3 dim1 128 dim2 128 dim3 60 dim4 1 dim5 1 dim6 1 dim7 1 vox_units mm time_units s datatype 16 nbyper 4 bitpix 32 pixdim0 0.0000000000 pixdim1 1.8750000000 pixdim2 1.8750000000 pixdim3 2.0999999046 pixdim4 0.0000000000 pixdim5 0.0000000000 pixdim6 0.0000000000 pixdim7 0.0000000000 vox_offset 352 cal_max 0.0000 cal_min 0.0000 scl_slope 1.000000 scl_inter 0.000000 phase_dim 0 freq_dim 0 slice_dim 0 slice_name Unknown slice_code 0 slice_start 0 slice_end 0 slice_duration 0.000000 time_offset 0.000000 intent Unknown intent_code 0 intent_name intent_p1 0.000000 intent_p2 0.000000 intent_p3 0.000000 qform_name Aligned Anat qform_code 2 qto_xyz:1 -1.875000 0.000000 -0.000000 119.062500 qto_xyz:2 0.000000 1.875000 -0.000000 -119.062500 qto_xyz:3 0.000000 0.000000 2.100000 -61.949997 qto_xyz:4 0.000000 0.000000 0.000000 1.000000 qform_xorient Right-to-Left qform_yorient Posterior-to-Anterior qform_zorient Inferior-to-Superior sform_name Aligned Anat sform_code 2 sto_xyz:1 -1.875000 0.000000 0.000000 119.062500 sto_xyz:2 0.000000 1.875000 0.000000 -119.062500 sto_xyz:3 0.000000 0.000000 2.100000 -61.949997 sto_xyz:4 0.000000 0.000000 0.000000 1.000000 sform_xorient Right-to-Left sform_yorient Posterior-to-Anterior sform_zorient Inferior-to-Superior file_type NIFTI-1+ file_code 1 descrip FSL5.0 aux_file