Dear Faezeh,
On 31 May 2017, at 19:20, Faezeh Vedaei wrote:
> Dear Dr. Gaser
> Thank you for your response. I do not have any idea why everything is
> weird for this data among many other flair data I have done LST
> segmentation. I tried applying LGA algorithm again by using several
> threshold between 0 and 1. The outputs show nothing yet. In case I
> would like to ask you this, the only difference between this data with
> other our data is that in this Flair data some parts of the bottom of
> the brain is cut, but I thought it may not affect our result. So, is
> this possible this is the reason this segmentation could not be done
> well?
Maybe you just found the reason for the failed segmentation. Brains
without full FOV are always a mess to process and this will usually
fail.
Best,
Christian
> RegardsFaezeh
>
> On Wednesday, May 31, 2017 11:48 AM, Christian Gaser
> <[log in to unmask]> wrote:
>
>
> Dear Faezeh,the LGA approach can be adapted to your data using
> different thresholds. You can define a row of different values between
> 0..1 to get lesion results for these
> thresholds.Best,ChristianChristian Gaser, Ph.D.
> Professor of Computational Neuroscience/Neuroimaging
> Biomagnetic Center
> Structural Brain Mapping Group
> Department of Neurology
> Jena University Hospital
> Am Klinikum 1, D-07747 Jena, Germany
> Tel: ++49-3641-9325778 Fax: ++49-3641-9325772
> e-mail: [log in to unmask]
> http://www.neuro.uni-jena.deOn 31 May 2017, at 17:46, Faezeh Vedaei
> wrote:
> Dear Dr. Gaser
> Thank you for your response. Actually, I tried using LGA algorithm as
> well, but the result of segmentation does not show anything. Indeed,
> the flair map (lesion part) is blank in this output, whereas we know
> that there are parts of hyperintensity lesion in white matter. So,
> what could be the problem? Do you think there is other way I can fix
> this problem? I really appreciate your help and time to us in this
> regard.
> Bests,Faezeh
>
> On Wednesday, May 31, 2017 10:08 AM, Christian Gaser
> <[log in to unmask]> wrote:
>
>
> Dear Faezeh,
>
> the LPA approach is based on the segmentation of the FLAIR images
> only, which sometimes results in less accurate results depending on
> the lesions in the image. This approach is mainly thought if you don't
> have an additional T1 image and/or it is difficult to find a stable
> threshold for the LGA approach. The multimodal segmentation of
> T1+FLAIR using the LGA approach might be the more appropriate approach
> if LPA fails. Fortunately, this only happens for one data set even if
> this is disappointing anyway. The LPA approach does not allow to
> control the segmentation using a threshold...
>
> Best,
>
> Christian
>
> On Mon, 22 May 2017 20:30:08 +0100, Faeze Vedaei <[log in to unmask]>
> wrote:
>
>> Hi SPMers
>>
>> I have used LST toolbox on SPM (LPA algorithm) to do Flair
>> segmentation to hyperintensity regions many times. The issue is that
>> for just one of my subjects which Fair data seems OK, the results of
>> LPA does not make sense. Indeed, Flair map as the result of Flair
>> segementation is so exaggerated by enlarged hyperintensity areas. I
>> do not have any idea why this happened to this data and how I can fix
>> that to a real segmented result. Here, I provided two screen shots of
>> original Flair and Flair map (result of segmentation) superimposed on
>> Flair data, you can see and compare how hyprintensity areas are in
>> different size is these two images. Any help to solve my problem is
>> appreciated and please let me know if you need some more information.
>> Thank you so much.
>>
>> Regards,
>> Faezeh Vedaei
>>
|