hi experts,

       I'm new for DTI, and I have two questions for DTI data analyss.

       1: For each subject, the bvec generated by dcm2nii or mriconvert are similar, but neither was same with the standard siemens directions provided by diffusion toolkit or others. Should i use individual bvec or standard siemens bvec? I tried both for fiber tracking, but the results are quite different.

       2, I used both eddy_crrected (by FSL) and raw data for fiber tracking using traditional FACT, the results were different for quite a few fibers (the direction, length and streamlines couts). As my aim is to find the differences of fibers in two group, I wonder if the eddy_correct step will make my results more credible or suspect? A Siemens engineer told me that the system did some eddy current correction during the scan, but maybe the eddy_correct more precise?

       Thank you for any advice or discussion.

 

        Mozi