Many thanks for your reply!
 
Regards,
 
Yan
 
> Date: Wed, 30 Jun 2010 18:34:25 +0200
> From: [log in to unmask]
> Subject: [FSL] AW: [FSL] AW: [FSL] corpus callosum waytotal
> To: [log in to unmask]
>
> fine!
> remember - a bg waytotal just means lots of samples make it from seed to target
> cheers,
> a.
> ________________________________________
> Von: FSL - FMRIB's Software Library [[log in to unmask]] im Auftrag von LiuYan [[log in to unmask]]
> Gesendet: Mittwoch, 30. Juni 2010 13:02
> An: [log in to unmask]
> Betreff: Re: [FSL] AW: [FSL] corpus callosum waytotal
>
> Hi Andreas:
>
> You are right, the extent of the tarct is not modified by the normalization, but being devided by a big waytotal will decrease the max value of the probability and then later I much use a low threshold for a good looking tract.
>
> We try to track the corpus callosum separately: the genu of the CC, the body of CC and the splenium of the CC (different ways of segmentation in the literature), and the results of the waytotal number is quite big. A threshold of 0.005 seems ok, what do you use for the adult?
>
> Regards,
>
> Yan
>
> the Given our population is the neonate, we use a threshold of 2%
>
> > Date: Wed, 30 Jun 2010 12:05:17 +0200
> > From: [log in to unmask]
> > Subject: [FSL] AW: [FSL] corpus callosum waytotal
> > To: [log in to unmask]
> >
> > no - you need to add the waytotal, given that the fdt_path is the sum of the tracking forth and back in the symm mode.
> > spatial extent of the tract is NOT modified by the normalization but only by later thresholding. depending on your masks, the numbers can seem quite low.
> > cheers-
> > andreas
> > ________________________________________
> > Von: FSL - FMRIB's Software Library [[log in to unmask]] im Auftrag von LiuYan [[log in to unmask]]
> > Gesendet: Mittwoch, 30. Juni 2010 12:04
> > An: [log in to unmask]
> > Betreff: Re: [FSL] corpus callosum waytotal
> >
> > Hi Stam:
> >
> > Thank you for your advice! I also thought of that, to use the sum for the normalization. But the waytotal number of the corpus callosum is big, if I add these two numbers and divide the fdt_path by the sum, I will have a very low probability for the entire tract. After using the threshold, I get very few fibres. Could I use the average of these two numbers, as it is the same tract going through the two seeds twice?
> >
> > Regards,
> >
> > Yan
> > ________________________________
> > Date: Wed, 30 Jun 2010 10:21:43 +0100
> > From: [log in to unmask]
> > Subject: Re: [FSL] corpus callosum waytotal
> > To: [log in to unmask]
> >
> > Hi Yan,
> >
> > you are right, you will get two waytotal numbers, one per specified seed mask. I would add these numbers and use the sum for normalization.
> >
> > Cheers,
> > Stam
> >
> >
> >
> > On 30 Jun 2010, at 09:50, LiuYan wrote:
> >
> > Hi FSL specialists:
> >
> > Recently, we try to do the tractography for the corpus callosum. Two seed masks are defined either side of the midline in the sagittal images. In the tools box, we choose the multiple masks to get the tract. However, we have two waytotal numbers in the result, and we don't know which one to use for the normalization. Any one who has also worked on the corpus callosum could give us some advice? Many thanks in advance!
> >
> > Regards,
> >
> > Yan
> >
> >
> >
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