[Mrtrix-discussion] csd equivalent of FA

[J-Donald Tournier]

Hi Alessandro,

Well, at heart AFD really is only the amplitude of the FOD along the fibre
direction of interest - actually, technically it's the integral of the FOD
over the FOD peak. You can compute the FOD amplitude in the old version,
but all the tools to compute the integral are in MRtrix3...

Besides, to really do AFD justice requires some fairly complex
preprocessing steps to ensure values can be compared across subjects, which
we still haven't documented properly. They're all currently implemented in
MRtrix3 - this is where all the development effort is going. While you
probably could hack something together using the old version, my
recommendation would be to upgrade and wait for the documentation to be
updated (hopefully not too long after the ISMRM...).

Even if you do want to stick with the old version, the steps required will
at least be documented on the MRtrix3 wiki, so you'll be able to see for
yourself how feasible this might be...

Cheers,
Donald
On 28 May 2015 5:41 pm, "Alessandro Calamuneri" <alecalamuneri at gmail.com>
wrote:

> Hi Donald,
> thanks for quick answering..
> Given I am using old mrtrix version (0.2), what could be a pipeline for
> calculating AFD?
>
> Thanks,
> Alessandro
>
> 2015-05-28 18:03 GMT+02:00 J-Donald Tournier <jdtournier at gmail.com>:
>
>> Hi Alessandro,
>>
>> Yes, that particular question has come up many times over the years... I
>> think we have a suitable answer now: apparent fibre density (
>> http://www.ncbi.nlm.nih.gov/pubmed/22036682). And this will probably be
>> improved further using multi-tissue CSD (
>> http://www.ncbi.nlm.nih.gov/pubmed/25109526)...
>>
>> Hope this answers your question.
>> Cheers,
>> Donald
>> On 28 May 2015 4:00 pm, "Alessandro Calamuneri" <alecalamuneri at gmail.com>
>> wrote:
>>
>>> Hi mrtrix experts,
>>>
>>> I would like to know whether there exists a csd based measure that might
>>> be considered the equivalent of Fractional Anisotrpy.
>>>
>>> Best Regards,
>>> Alessandro
>>>
>>>
>>> _______________________________________________
>>> Mrtrix-discussion mailing list
>>> Mrtrix-discussion at www.nitrc.org
>>> http://www.nitrc.org/mailman/listinfo/mrtrix-discussion
>>>
>>>
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.nitrc.org/pipermail/mrtrix-discussion/attachments/20150528/72fd15a2/attachment.html>