[Mristudio-users] fiber tracking

[susumu mori]

Hi Sona,

There is detailed description about the "flip" function in the manual. the
truth is, nobody is sure about the sign because scanners can change it
dynamically depending on your scan protocol.
There is a way to rigorously solve this problem, but it is very difficult
and that's why we just empirically solve it by checking all 4 options (no
check, x, y, z flipped). Good news is, if the signs are wrong, tracking
doesn't make sense.

On Fri, Jan 8, 2010 at 10:34 AM, Sona Saksena <saksena.sona at gmail.com>wrote:

> Hi,
>
> Thanks for your suggestion. There is a option in the fiber tracking
> parameters "Flip Eigen Vector". Do I have to use this check box?
>
> Actually we have applied gradients in 26 directions (GE Scanner, 3Tesla). I
> am not sure about the sign of all of the components in the gradient
> table.  What shall I do?
>
> This is the gradient table.
>
>
> 0: 0.000000, 0.000000, 0.000000
>
> 1: 1.000000, 0.000000, 0.000000
>
> 2: 0.849000, 0.528000, 0.000000
>
> 3: -0.108000, 0.565000, 0.818000
>
> 4: 0.884000, -0.345000, -0.315000
>
> 5: -0.003000, -0.736000, 0.677000
>
> 6: -0.868000, -0.238000, 0.436000
>
> 7: 0.799000, 0.370000, 0.475000
>
> 8: -0.162000, 0.987000, 0.000000
>
> 9: 0.866000, -0.129000, 0.483000
>
> 10: -0.212000, -0.936000, 0.281000
>
> 11: 0.068000, -0.892000, -0.446000
>
> 12: 0.550000, -0.544000, -0.634000
>
> 13: -0.435000, -0.422000, 0.795000
>
> 14: -0.599000, 0.780000, 0.182000
>
> 15: -0.525000, 0.030000, -0.851000
>
> 16: -0.600000, -0.688000, 0.409000
>
> 17: 0.653000, -0.060000, -0.755000
>
> 18: 0.207000, -0.076000, -0.975000
>
> 19: -0.413000, -0.699000, -0.584000
>
> 20: -0.436000, 0.822000, -0.366000
>
> 21: 0.462000, 0.874000, 0.148000
>
> 22: -0.503000, 0.488000, -0.713000
>
> 23: 0.824000, -0.530000, 0.202000
>
> 24: 0.297000, 0.349000, 0.889000
>
> 25: -0.040000, 0.318000, -0.947000
>
>
>
> Please do suggest?
>
>
>
> regards
>
>
>
> sona
>
>
>
>
> On Thu, Jan 7, 2010 at 3:32 PM, susumu mori <susumu at mri.jhu.edu> wrote:
>
>> Hi Sona,
>>
>> I suggest you to go through the manual section in www.mristudio.org.
>> There you can find a user's manual for DtiStudio. It gives you the
>> step-by-step procedure for tensor calculation and fiber tracking.
>>
>>   On Thu, Jan 7, 2010 at 2:48 PM, Sona Saksena <saksena.sona at gmail.com>wrote:
>>
>>>   Hello,
>>>
>>> Please can you tell me steps of performing fiber tracking in brain tumor
>>> patients using DTI studio. The DTI data is on 3T GE scanner with gradients
>>> applied in 26 directions. How to generate the reconstructed fibres?
>>>
>>> thanks
>>>
>>> regards
>>>
>>> Sona Saksena
>>>
>>>
>>>
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>>
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>
>
> --
> Sona Saksena
> Ph. D Scholar
>
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