[Mrtrix-discussion] connectivity p and distance from seed

[Luis Concha]

Thank you, Kerstin, I was not aware of this paper, and it seems like it's
just what I need.

Luis

On Fri, Oct 5, 2012 at 12:42 AM, Kerstin Pannek <
kerstin.pannek at cai.uq.edu.au> wrote:

>  Hi Luis
>
>  I recently came across this paper
> http://www.ncbi.nlm.nih.gov/pubmed/18619548
> that deals with the distance effect by using a "null connection
> probability map" to compare the tractography results with.
>
>  Cheers
> Kerstin
>
>
>  On 05/10/2012, at 9:35 AM, Luis Concha <lconcha at gmail.com>
>  wrote:
>
> Hello.
>
>  Since tracking errors build up as streamlines propagate from the seed,
> and uncertainties in the PDFs are added, it is inevitable that the
> probability of connection of a given voxel from a seed is dependent upon
> its distance. As such, voxels far away from the seed often have very low
> probabilities of connection to the seed (even <1%). Compensating these low
> probabilities is often performed by multiplying the visitation counts per
> voxel by the average euclidean distance from the seed (this is how fsl
> does it<https://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind0805&L=FSL&D=0&P=80972>).
> The result, however, is uninterpretable, as it is impossible to disentangle
> the contribution of distance from diffusion-derived connectivity.
>
>  Does anybody in this list have a strategy to obtain reasonably high
> probabilities of connectivity to a distant seed that can be compared to
> those obtained in voxels that are closer to the seed? Could you recommend
> some papers discussing this issue? Any help will be most appreciated.
>
>  Thanks.
>
>  Luis Concha.
> _______________________________________________
> 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/20121005/46396d8d/attachment-0001.html