# Measure of fibre orientation dispersion in MRTrix3

**URL:** https://community.mrtrix.org/t/measure-of-fibre-orientation-dispersion-in-mrtrix3/674
**Category:** Uncategorized
**Created:** [January 21, 2017, 7:34pm UTC](https://community.mrtrix.org/t/measure-of-fibre-orientation-dispersion-in-mrtrix3/674 "2017-01-21T19:34:07Z")
**Posts on this page:** 1
**Showing post:** 2

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### 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: [January 23, 2017, 12:21am UTC](https://community.mrtrix.org/t/measure-of-fibre-orientation-dispersion-in-mrtrix3/674/2 "2017-01-23T00:21:43Z")

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Hi Carmen,

You can currently get a quantity that is _somehow_ proportional to fibre orientation dispersion using [`fod2fixel -disp`](http://mrtrix.readthedocs.io/en/latest/reference/commands/fod2fixel.html#metric-values-for-fixel-based-sparse-output-images). It’s literally just the integral divided by the peak amplitude of the FOD lobe, so it’s not ‘calibrated’ to e.g. a dispersion angle; but it should be small for sharp FODs and larger for fatter ones.

If you’re an ISMRM member, you can access my [2016 abstract](http://indexsmart.mirasmart.com/ISMRM2016/PDFfiles/3035.html), which presented a more sophisticated FOD post-processing algorithm trying to get at this quantity. It may eventually see the light of day if I ever find the time to get back to it. 😫

Cheers  
Rob

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