The intensity in each voxel of the image represents this number.
Cheers,
Stam
On 18 Jul 2011, at 13:04, Adil Javed wrote:
> Thanks so much. Since fdt_paths.nii.gz is an image file, how do you get the value M?
>
> many thanks,
> AJ
>
> --- On Mon, 7/18/11, Stamatios Sotiropoulos <[log in to unmask]> wrote:
>
>> From: Stamatios Sotiropoulos <[log in to unmask]>
>> Subject: Re: [FSL] Probabilistic tractography
>> To: [log in to unmask]
>> Date: Monday, July 18, 2011, 3:04 AM
>> Hi Aj,
>>
>> The "connectivity value" in probabilistic tractography from
>> a seed A to a voxel B is defined as the ratio M/N, where M
>> is the number of curves that start from A and go through B
>> and N the total number of curves starting from A. This ratio
>> gives an estimate of the probability of the path of least
>> hindrance to diffusion.
>>
>> The waytotal file gives you N, the total number of *valid*
>> curves that have started from A (after excluding curves that
>> do not meet exclusion/inclusion criteria). M for each voxel
>> in the image is described in the fdt_paths file. Dividing
>> the two will give path probabilities.
>>
>> Hope this is clear,
>> Stam
>>
>>
>> On 18 Jul 2011, at 09:04, Adil Javed wrote:
>>
>>> Hi,
>>> I have generated some data using tractography.
>> The waytotal text file shows a number. Is it more
>> accurate to report that number as connectivity value or an
>> estimate of number of fibers per seed/mask on a plot?
>>>
>>> many thanks,
>>>
>>> aj
>>>
>>
>
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