# Is it possible to do tractography within a range of FA?

**URL:** <https://community.mrtrix.org/t/is-it-possible-to-do-tractography-within-a-range-of-fa/7950>\
**Category:** Uncategorized\
**Tags:** tractography\
**Created:** [September 25, 2024, 8:12am UTC](https://community.mrtrix.org/t/is-it-possible-to-do-tractography-within-a-range-of-fa/7950 "2024-09-25T08:12:11Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![zzwang](https://community.mrtrix.org/user_avatar/community.mrtrix.org/zzwang/32/4464_2.png) [@zzwang](https://community.mrtrix.org/u/zzwang)\
**Post date:** [September 25, 2024, 8:12am UTC](https://community.mrtrix.org/t/is-it-possible-to-do-tractography-within-a-range-of-fa/7950/1 "2024-09-25T08:12:12Z")

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Hi!

I am trying to run the anatomically constrained tractography and wonder how I can set a range of FA. For example, I would love to run tractography with 0.1\<FA\<0.5. Is it possible to do this?

Thanks!  
Zhongzheng

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**Author:** ![shenzhao](https://community.mrtrix.org/letter_avatar_proxy/v4/letter/s/9fc348/32.png) [@shenzhao](https://community.mrtrix.org/u/shenzhao)\
**Post date:** [September 27, 2024, 10:04am UTC](https://community.mrtrix.org/t/is-it-possible-to-do-tractography-within-a-range-of-fa/7950/2 "2024-09-27T10:04:38Z")

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You can generate FA image by dwi2tensor+tensor2metric, and then get the mask image for 0.1\<FA\<0.5. Finally add " -mask {your fa mask image} " after tckgen command.

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**Author:** ![zzwang](https://community.mrtrix.org/user_avatar/community.mrtrix.org/zzwang/32/4464_2.png) [@zzwang](https://community.mrtrix.org/u/zzwang)\
**Post date:** [September 27, 2024, 3:07pm UTC](https://community.mrtrix.org/t/is-it-possible-to-do-tractography-within-a-range-of-fa/7950/3 "2024-09-27T15:07:45Z")

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Thanks for the tip!