Hello Jan,
indeed, the number in the waytotal file is the total number of generated tracts that reach your waypoint mask.
When you compute the total sum using all the voxels within your waypoint mask, though, you are very likely to get a number higher thank the waytotal because a single streamline can run through several voxels of your waypoint mask (i.e., it will be counted multiple times).
When you are using the same mask as a waypoint and termination mask you prevent that from happening.
Cheers,
Matteo
> On 6 Jun 2017, at 13:18, Jan Kurzawski <[log in to unmask]> wrote:
>
> Dear FSL people,
>
> I am running probtrackx2 from one seed using one waypoint. My waytotal value is equal to 133. When I open the tract in matlab and sum all the points within the waypoint ROI I end up with value of 730.
>
> Isn’t waytotal representing exactly the number of the streamlines that has been accepted within the ROI (waypoint)?
>
> When I run the same command but I add the termination mask (same as waypoint) I get a value of waytotal of 141 (shouldn't it be less when I terminate compared to when I let the tract to go further?). In this case the waytotal it is exactly the same as the sum of stream lines within the ROI.
>
> Could anybody explain the difference?
>
> BR,
> Jan Kurzawski
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