Dear MRtrix3 experts,
I have a segmented tract in .tck format. My aim is conducting an along-tract analysis. I would like to resample my tract along its longitudinal axis to obtain the points I would get if I ideally cut it with a series of equidistant planes placed orthogonally to its longitudinal axis.
To do so, I used the command:
tckresample -line x a,b,c d,e,f input.tck output.tck
x being the number resampling locations, and
d,e,f the coordinates between which to resample (i.e. the endpoints of the resampling line).
My questions are: (i) which would be the most reasonable approach for choosing the coordinates between which to resample in your opinion?
It seems that if I indicate some coordinates which are more extreme (i.e. more anterior and more posterior for a tract oriented along the y axis as in my case) than the tract’s endpoints, the output is an empty image. From the tests I did, if I am not getting it wrong, it seems that for a streamline, to be successfully resampled it is necessary that its endpoints are as extreme or more extreme than the ones of the resampling line. However, if one desires to not lose any streamlines (in terms of number of streamlines), this - again, if I am not getting it wrong - would restrict the resampling only to the part of the tract in which all the streamlines are present.
So my second question is: (ii) is there a way to include all the tract in the resampling procedure? In other words, to keep both the number of streamlines and their length (not lose the extreme parts)?
Thank you very much for your attention and for any help.