[Mrtrix-discussion] streamline numbers at two b-values

[Donald Tournier]

Hi Kerstin,

I have to admit, I'm not too sure about that. My best guess is that
since the low b-value FODs are (presumably) smoother, more of them
start in the 'right' direction, and a greater proportion of them
manage to exceed the minimum length threshold. This is just a guess,
I'd have to really dig down to give you a definitive answer though...

Cheers,

Donald.


On Fri, Nov 13, 2009 at 3:10 PM, Kerstin Pannek <k.pannek1 at uq.edu.au> wrote:
> Hi all
>
> I have two DWI datasets acquired per participant, one with b-value 1000, and
> another with b-value 3000. I performed whole brain tractography for both
> datasets, seeding 1 streamline per mm3:
>
> $ streamtrack SD_PROB csd.mif -seed brain_mask.nii -number 103127 -maxnum
> 103127 wb.tck
>
> The number of accepted streamlines is about 30% higher for the b1000 data
> than for the b3000 data. This is consistent across all participants.
>
> I was just wondering why that is?
>
> Thanks
> Kerstin
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-- 
Jacques-Donald Tournier (PhD)
Brain Research Institute, Melbourne, Australia
Tel: +61 (0)3 9496 4078