Hi:

  I tried to use trac-all using following syntax:

trac-all -prep -s name -i SIEMENS_DICOM_256_GRADIENTS_TRACTOGRAPHY_FILES_PATH

and I got the following error message:

"ERROR: for B0 distortion correction with reverse-polarity DWIs
ERROR: or for model-based eddy-current distortion correction,
ERROR: must specify PE direction"

  Why?

  Sincerely,