Hi - If your seedmasks are defined in structural space, then the streamlines are sent off from all voxels within your seed in structural space, so you need to multiply by the number of voxels in structural space.
Saad
On 13 Feb 2012, at 18:24, Cunningham, Dustin wrote:
> Greetings,
>
> Using a one mask and one target approach that are defined in structural space (1mm^3) I have obtained a fdt_paths file and waytotal for visual and quantitative information, respectively. If I ask the question "what proportion of the streamlines from my seed reached my target?" seemingly all I would do is waytotal divided by total streamlines sent out. For total streamlines I multiply the number of voxels in the seed mask by 5000 (default). My question is do I use the total number of voxels in my seed mask in diffusion space (2mm^3 roughly) which will obviously be significantly less than the total number of voxels in my structural? And, out of curiosity, this would mean there are less than 5000 streamlines being sent out in the structural because the voxels are smaller?
>
> Thanks,
> Dustin
>
--
Saad Jbabdi
University of Oxford, FMRIB Centre
JR Hospital, Headington, OX3 9DU, UK
(+44)1865-222466 (fax 717)
www.fmrib.ox.ac.uk/~saad
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