Hi, I have some Philips 3T (Intera) diffusion images for which I am using "fslroi" to get the b0 image. I see different behavior in FSL6 compared to FSL5.0.9:

1) the output datatype is different. The DWI volume is INT16, and "fslroi" returns INT16 (FSL6) or FLOAT32 (FSL5).
2) the voxel value ranges are drastically different:

I did the same thing, extracting the first volume of a 4D resting-state fMRI series, but the output was (nearly) identical.

I can't figure out what the issue is. This is on CentOS 7.4.1708; GCC 5.4.0; openblas 0.3.4

I am happy to provide any other information.

Chris