I analyzed a lot of brains in Freesurfer. For some reason some brains gets cut on the top (see attaced image). I cannot understand why this is happening. The dicom image is ok, but as soon as I convert it into mgz suddenly the top of the brain is cut off. 

Out of 60 brains with identical mri sequence 5 brains are cut.

Would be grateful if you suggest how to solve this problem

Thanks in advance!

Olof