0 values from tcksample

1

Hello,

I am using the tcksample function to obtain FA, RD, MD and AD measurements for my tractography. In some of my participants, the values in the csv files for all measurements are 0 (attached image). I have checked the tractography and it is the same as all the other participants. The script I have used for all the participants are:

tcksample label_7.tck FA.mif label_7_FA.csv
tcksample label_7.tck MD.mif label_7_MD.csv
tcksample label_7.tck RD.mif label_7_RD.csv
tcksample label_7.tck AD.mif label7_AD.csv

Is there any idea what could be wrong here?

Thanks!

Regards,
Akila

Screenshot 2021-07-14 at 10.25.59
Screenshot 2021-07-14 at 10.25.591920×1080 149 KB

2

Hi Akila,

The first thing to check is whether or not there is actually spatial correspondence between the streamlines data and the image data. If the two don’t overlap, then one can’t expect tcksample to produce any sensible result. Are you able to load one of those tensor metric images in mrview, open your .tck file using the Tractography tool, and have them appear in the same location?

Rob