[Mristudio-users] broken and thick fibers

[Durai Arasan]

On Fri, Mar 8, 2013 at 6:58 PM, Durai Arasan <durai23 at gmail.com> wrote:

> Thanks! The gradient table was extracted from the dicom header.
>
> As you can see in the picture in the next message, no flipping gives rise
> to best (corpus callosum) results among all 7 permutations. This is a new
> siemens scanner.
>
> Can anyone comment on the effect of pixel size, slice thickness and noise
> on fiber quality?
>
> On Fri, Mar 8, 2013 at 7:20 AM, susumu mori <susumu at mri.jhu.edu> wrote:
>
>> As Anonim mentioned, the most common mistake is the sign of the gradient
>> table.
>> Please read page 23 of the manual here (
>> https://www.mristudio.org/wiki/user_manual).
>> If you feed a gradient table based on a generic table, you need to figure
>> out the +/- sign of the vector elements.
>>
>> Recent DICOM headers contain vector information with correct +/- signs.
>> So, it is easier to use the function to extract the gradient table from the
>> header.
>>
>>
>> On Thu, Mar 7, 2013 at 1:35 PM, Anonim <albnet at gmail.com> wrote:
>>
>>> Try flipping the eigenvector for direction X, Y, or Z. Its typical to
>>> have short fibers when one of the eigenvectors need to be flipped.
>>>
>>> Dorian
>>>
>>> 2013/3/7 Durai Arasan <durai23 at gmail.com>
>>>
>>>> Hi all
>>>>
>>>> I am tracking with data that has slice thickness = 3 and pixel size =
>>>> 1.65.
>>>>
>>>> I have a lot of broken fibers i.e. the path of the fiber is interuppted.
>>>>
>>>> My fibers are also quite thick (large diameter) and less dense (low
>>>> number of fibers/area).
>>>>
>>>> Any comments on why this is observed?
>>>>
>>>> Thanks
>>>>
>>>>
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>>>
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>>
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>
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