Dear DTIPrep developers, 

 Thank you for this extremely useful tool. I would like to extract motion parameters from the Eddy currents and motion artifact detection step. In the QCReport.txt file, there is a list of parameters for every gradient, with 12 parameters for each gradient. I assume they are derived from the affine transformation matrix, but I cannot figure out the correct order of these parameters and which one is which.

I guess that the first, the the 5th and the 9th are the scaling factor (x,y,z) as they are close to one, but I might be wrong. 

Thus, are the others, x,y and z for rotation, translation, and...?

Could you please clarify this simple question?

ie:

• Parameters: [0.9940250406542067, 0.005037731155539504, -0.0044764617213477525, -0.003336387327671193, 0.9906213568620513, -0.001621771668964308, 0.002073337608179639, 0.0009743273562393963, 0.9919877206204243, -0.1478211258441959, -0.023645834340927947, 0.06009304791091765]

Thanks in advance

Dani Bergé

Hospital del Mar Research Institute

Barcelona, Spain