Hi Teresa,

What are the current voxel dimensions for your image?
If they exceed 5mm in any direction, was this due to downsampling spatial
resolution from the acquisition scan?

If you acquired images at a higher spatial resolution than the image you
are trying to process and downsampled, you should use the original higher
spatial resolution images. Otherwise, I'm not certain whether you should
trust data that has been fit to higher resolution space for any processing.

Cheers,
Paul