[Mristudio-users] DTI normalization with Diffeomap on lesioned brains

[Dorian P.]

Thank you for answering Dr. Mori,

Would it be feasible to mask only the lesion on the patient or does it have
to be on both patient and atlas?

Has anybody compared a T1 normalization on SPM and applying the matrix to
DTI to a low elasticity normalization in DTIstudio?

Best regards.
Dorian


2012/11/30 susumu mori <susumu at mri.jhu.edu>

> In general, lesions (severe intensity changes) or severe anatomical
> changes (e.g. missing tissues or tumor) are very difficult to deal with,
> when you are using a transformation-based analysis.
>
> When you use transformation with low elasticity (e.g. linear
> transformation), the transformation could be less affected because the
> registration would be mostly driven by the brain outlines. So, if your
> lesions (intensity changes) do not accompany anatomical deformation, you
> may be able to compare patients and controls.
>
> As the elasticity increases, the transformation would be more affected by
> the lesions. Of course, if the lesions are small, they may not cause much
> problems but I assume you have large lesions.
>
> If you are studying, for example, stroke and interested in anatomical
> changes of contralateral hemisphere (or the brainstem), you can mask-out
> the ipsilateral hemisphere for both patients and the atlas. We have done
> this type of analyses before.
>
> Sorry that I could give you only a generic answer. This is an issue that
> the whole community faces.
>
> On Fri, Nov 30, 2012 at 2:52 PM, Dorian P. <alb.net at gmail.com> wrote:
>
>> Hi all,
>>
>> I am interested on normalizing lesioned brains with a dual channel
>> Diffeomap procedure. The normalization will be done on MNI existing
>> template of Diffeomap. Lesions typically come from surgical resections.
>>
>> Does this procedure work well on lesioned brains or shall I need some
>> mask for Diffeomap to avoid normalizing the lesioned area?
>>
>> Any comment is welcome. I couldn't find much about the topic on previous
>> posts and articles.
>>
>> Thank you.
>> Dorian P
>>
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