Dear Mr. Papademetris,

thanks for your quick reply. I was able to partially solve the problem by just re-orienting the image to the RAS orientation in the image editor. Unfortunately, I could not find the variable "forceBISorientation" under Preferences->file format, but manually re-orienting should be fine.

However, when I try to threshold the image after re-orienting, I get a VTK error message (attached)

Thanks again,
Johann Philipp Zöllner