There are lots of ways to do this. See this previous thread and the links included there too:
3dinfo looks at the header of the dataset to see what space it is. AFNI and NIFTI headers both have fields for this. That is sometimes not correctly set. If you know that the data is in one of the MNI spaces, then you can fix that in the dataset with 3drefit or nifti_tool. Here's a simple example with 3drefit:
The
National Institute of Mental Health (NIMH) is part of the National Institutes of
Health (NIH), a component of the U.S. Department of Health and Human
Services.