Visualizing t-statistics from age effects on tracts with mrview

Hi MRtrixperts,

I am interested in typical developmental effects of fixel metrics:

Some mean metric of different WM bundles ~ age + sex

For visualization purposes, I am trying to color the different WM bundle (tracts) based on the age t-value from my statistical model in mrview. I know it is possible to do so by loading a .txt file in the option of mrview in tractography. Does anyone have an example of such .tsf or .txt file? I have created a .txt file with the t-value, but it’s wrong because I always get:

The scalar text file does not contain the same number of elements as the selected tractogram

How should one create this .txt file?

Thank you for all the help,

Hi Josiane,

There’s a big difference between the operation of a .tsf vs. .txt file here. The former allows you to attribute some value per streamline vertex, whereas with the latter you can only attribute a value per streamline. If you have a statistical model parameter that is defined per fixel, the former simply involves sampling at each streamline vertex the value stored within the underlying fixel (currently via fixel2tsf). The latter would necessitate at least one extra operation.

What you’re most likely looking for (the former) is described in this Wiki page.


Thanks Rob for the explanation !