Dear FreeSurfer Team, I am working with two timepoints for a subject and attempting to create a template for samseg-long using mri_robust_template. However, I encountered an error related to voxel size mismatch between the input images. Both timepoint images are T1W. The command I ran is:

mri_robust_template --mov subject1_preRT.nii subject1_postRT.nii --template mean.mgz --satit --mapmov subject1_preRT_reg.mgz subject1_postRT_reg.mgz

I received the following error:

ERROR: MultiRegistration::loadMovables: images have different voxel sizes. Currently not supported, maybe first make conform? Debug info: size(1) = 0.428571, 0.428571, 4.4 size(0) = 0.449219, 0.449219, 5 error: Operation not permitted error: MultiRegistration::loadMovables: voxel size is different subject1_postRT.nii.

From what I understand, mri_robust_template does not support different voxel sizes between input images. Would the recommended approach be to first resample the images to the same voxel size using mri_convert --conform or another method before running mri_robust_template?

Additionally, would this resampling introduce any potential biases that I should be aware of in a longitudinal analysis? If there is a better way to handle this issue, I would greatly appreciate your guidance. Best regards, Nima