Hi, I'm not sure but I think that the option --kurtdir has not been implented yet. So basically when you put this option, basically you are fitting the standard DTI model, if you fit the model with or withou --kurtdir, the result should be the same. This is the reason why is higher than the --kurt option. For multishell data the --kurt parameter is the best option. Best regards, Manuel ######################################################################## To unsubscribe from the FSL list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=FSL&A=1