Dear Freesurfer community,
We've encountered a strange situation where the pial and wm surface delineation is successful for one image but contains wm (and subsequent pial) errors for another, almost identical structural image (see attached image, red and yellow are for the successful surface and blue and green are for the failed one). We've tried to identify the source for this discrepancy but I'm at a loss. All voxels of the original input images are identical to the 4th decimal and when converted to orig.mgz only a few voxels appear to be different due to rounding, none of which overlap with the wm surface errors. Both images were processed on the same setup (hardware and software, Freesurfer stable 5.3). Unfortunately, this error is quite systematic in my dataset; about 10% of the images show this type of error. Any suggestions on how to investigate this? I've uploaded example of good and bad at recon ftp://surfer.nmr.mgh.harvard.edu/transfer/incoming/failed_wm_recon.tar.gz in case you'd like to have a closer look.
Thanks for your help.
Vincent and Melanie
