thanks a lot Mark, it worked! I've performed succesfully a volumetry over a 218X130X213 image (and also over others of lower resolution) However, when I try to use sienax on a higher resolution image (512X512X248) I'm getting errors and finally a segmentation fault (see below). Perhaps this has something to do with the resolution of the images, or there is an extra problem? thanks a lot! Enzo ---- * ERROR: nifti_image_open(I_stdmaskbrain_pve_1): bad header info Error: failed to open file I_stdmaskbrain_pve_1 ERROR: Could not open image I_stdmaskbrain_pve_1 Image Exception : #22 :: Failed to read volume I_stdmaskbrain_pve_1 dc: stack empty dc: stack empty dc: stack empty dc: stack empty ** ERROR (nifti_image_read): failed to find header file for 'I_stdmaskbrain_pve_2' ** ERROR: nifti_image_open(I_stdmaskbrain_pve_2): bad header info Error: failed to open file I_stdmaskbrain_pve_2 ERROR: Could not open image I_stdmaskbrain_pve_2 Image Exception : #22 :: Failed to read volume I_stdmaskbrain_pve_2 dc: stack empty dc: stack empty dc: stack empty dc: stack empty ** ERROR (nifti_image_read): failed to find header file for 'I_stdmaskbrain_seg' ** ERROR: nifti_image_open(I_stdmaskbrain_seg): bad header info Error: failed to open file I_stdmaskbrain_seg ERROR: Could not open image I_stdmaskbrain_seg Image Exception : #22 :: Failed to read volume I_stdmaskbrain_seg terminate called after throwing an instance of 'RBD_COMMON::BaseException' Aborted ** ERROR (nifti_image_read): failed to find header file for 'I_render' ** ERROR: nifti_image_open(I_render): bad header info Error: failed to open file I_render ERROR: Could not open image I_render Image Exception : #22 :: Failed to read volume I_render terminate called after throwing an instance of 'RBD_COMMON::BaseException' Aborted Cannot open grIa.png for reading Segmentation fault /bin/rm: cannot remove `grI?.???': No such file or directory