[Mrtrix-discussion] direction Scheme - bvecs - encoding.b - diffrence - Siemens MRI Scanner

[Luetzkendorf, Ralf]

Hi to all,

I have a little problem with the vector scheme.

I noticed a sign difference between the scanner directions, that I fill in and MRTrix reading out from the data.
Even if Im measuring straight axial, like the documentation said.
I hope that is normal.

Is it okay to use them both or should I ever use the directions that MRTrix is gathering from the data?


Now I have a second problem. I used the same direction scheme like before, but now MRTrix doesnt only change the signs.
It has different values for every B0 data set. The other values are still the same.

The B0 direction looks like that:

0.5 -0.5 0.707107 5

instead of:

0 0 0 0


Did somebody encouter the same problem? Which should I use?

I hope somebody can help,


Cheers Ralf

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Ralf Lützkendorf
Department for Biometry and Medical Informatics
University of Magdeburg, Germany