# FD/FC/FDC for a single tract **URL:** https://community.mrtrix.org/t/fd-fc-fdc-for-a-single-tract/1605 **Category:** Uncategorized **Created:** [May 4, 2018, 1:23am UTC](https://community.mrtrix.org/t/fd-fc-fdc-for-a-single-tract/1605 "2018-05-04T01:23:37Z") **Posts on this page:** 1 **Showing post:** 2
### Author: ![rsmith](https://community.mrtrix.org/user_avatar/community.mrtrix.org/rsmith/32/2672_2.png) [@rsmith](https://community.mrtrix.org/u/rsmith) #### Post date: [May 18, 2018, 3:57am UTC](https://community.mrtrix.org/t/fd-fc-fdc-for-a-single-tract/1605/2 "2018-05-18T03:57:59Z")
Hi Sarbani, It sounds like you’re trying to do something similar to other recent posts; e.g. see [here](http://community.mrtrix.org/t/extracting-rois-for-fixel-based-analysis/1614/2). But I’ll try to address these in turn as best I can: > How can I read the value of FD or FC or FDC from a single voxel for an individual subject? `voxel2fixel` using a ROI containing a single voxel will generate a fixel mask selecting only those fixels within that one voxel. You could then access the raw metric values using `mrdump -mask`. You could even generate the single-voxel ROI at the command-line using the `mredit` command if you so desired. > For a streamline how can I calculate FD FC FDC for each of the fibre bundles ? One would not normally describe a solitary streamline having an association with a plurality of “fibre bundles”… Do you perhaps mean that you want the FD / FC / FDC values for all _fixels_ traversed by an individual streamline? Unfortunately while `tcksample` is the logical place to look for such a functionality, it does not yet have the capacity to work with fixels (that’s one small part of a large software update I’ve been working on for ages, and may finish before the end of the universe if I’m lucky). You could however pull a bit of a trick by using the `tck2fixel` command, followed by `mrthreshold -abs 0.5`, to get a fixel mask containing only those fixels traversed by that particular streamline. You would however lose in this process the information regarding the order in which those fixels were traversed. Rob --- _[View the full topic](https://community.mrtrix.org/t/fd-fc-fdc-for-a-single-tract/1605)._