[Mrtrix-discussion] connectivity p and distance from seed

[Kerstin Pannek]

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<mailto: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<mailto: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/ca793b67/attachment.html