[Freesurfer] Tracula: Calculation of MD values from other eigenvectors

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Dear Tracula Experts,

We are trying to address a question from a reviewer who is wondering why we included all of the average diffusion parameters in our model ( i.e. FA, MD,FA, RD, and AD) for distinguishing two groups of patients . The reviewer comments that MD values are calculated from AD and RD henceforth, including of all of the three parameters ( AD, RD, and MD) might have biased our analysis. I understand the reviewer’s concern that MD is calculated from adding all three eigenvalues/3, but I am uncertain about the relationship between the eigenvalues and the calculation of ‘average’ parameters for a given fibertract.

I am looking forward to your guidance, With kind Regards, Catherine