On Wed, Apr 24, 2013 at 2:35 PM, wolf zinke <[log in to unmask]> wrote:

On 04/24/2013 11:14 PM, Dana Wagshal wrote:

Hi FSL group,

I have ROIs in 2mm MNI standard space and I want to convert them TO 1mm MNI space. I used this command:

  flirt -in lACC.nii.gz -ref /usr/share/data/fsl-mni152-templates/MNI152_T1_1mm_brain -applyxfm -out lACC_1mm

However, when I typed in fslinfo for both the original and new ROI, I saw that the dimensions were changed. Is this ok or should the dimensions be the same?

If you mean by dimension the dim values, it is to be expected, that you need double the voxel to cover the same volume if you use half the voxel size. For ROI masks it might be good to binarize them (fslmaths -bin).

Otherwise if the transformed ROIs look on a 1mm standard brain the same as the olf ROIs on a 2mm brain, it should be fine.

Good luck,
wolf

Below is the information:

fslinfo lACC-new.nii.gz

data_type      INT16
dim1           91
dim2           109
dim3           91
dim4           1
datatype       4
pixdim1        2.0000000000
pixdim2        2.0000000000
pixdim3        2.0000000000
pixdim4        0.0000000000
cal_max        4.0000
cal_min        0.0000
file_type      NIFTI-1+

fslinfo lACC_1mm.nii.gz

data_type      FLOAT32
dim1           182
dim2           218
dim3           182
dim4           1
datatype       16
pixdim1        1.0000000000
pixdim2        1.0000000000
pixdim3        1.0000000000
pixdim4        0.0000000000
cal_max        0.0000
cal_min        0.0000
file_type      NIFTI-1+

Best,
Dana