Hi John,
The latest version of FDT does output as many line in waytotal as seed
masks. So in the two masks mode it has two lines, and in the multiple
masks mode it has multiple lines!
Steps 1-6 look fine to me. Keep in mind that they are just heuristic
though.
Cheers,
Saad.
On 14 Nov 2008, at 12:49, John D. Griffiths wrote:
> Hi Saad,
> Any news on that patch to output waytotal files for
> twomasks/network mode? Or did it make it into FSL 4.1 in the end?
>
> I'm guessing not, so can I just check that I've got this right:
>
> I can apply an objective and appropriate threshold to a 2-ROI
> tractography
> analysis by doing the following:
>
> 1. Track from mask A with mask B as a waypoint, giving me an ROIA--
> >ROIB
> fdt_paths image and corresponding waytotal file,
>
> 2. Do vice versa: track from mask B with mask A as a waypoint,
> giving an
> ROIB-->ROIA fdt_paths image and waytotal file.
>
> 3. Threshold the ROIA-->ROIB image as a proportion of the number in
> the
> ROIA-->ROIB waytotal file.
>
> 4. Do vice versa.
>
> 5. (key point) - Sum the two thresholded images (?)
>
> 6. Do all further post-tractography analyses on this data.
>
> Would that be correct?
>
> Seems like a long haul, but this is preferable to thresholding as a
> proportion of the total number of streamlines sent out (i.e. size of
> the
> seed masks).
>
> Anyone any other suggestions for objective ways to threshold 2-ROI
> tractography results?
>
>
> Cheers,
> John
>
Saad Jbabdi
Oxford University FMRIB Centre
JR Hospital, Headington, OX3 9DU, UK
+44 (0) 1865 222545 (fax 717)
www.fmrib.ox.ac.uk/~saad
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