On 2/14/19 12:16 PM, Matthieu VANHOUTTE wrote:
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>
> Hi Douglas,
>
> So to register PET to gtmseg space mri_gtmpvc command use nearest
> neighbor, interpolation right ?
It does not map the PET to the gtmseg space. It maps the gtmseg to the
PET space. Since this is a segmentation, it uses nearest neighbor. But
the algorithm is much more complicated; see the paper.

>
> And what about the interpolation method to use when projecting PVE
> corrected PET on surface  ?
I usually use nearest neighbor to avoid interpolation

>
> Thanks,
>
> Matthieu
>
> On 14/02/2019 17:44, Greve, Douglas N.,Ph.D. wrote:
>> The GTM operates on regions, so you can't do trilin interp. The
>> operations that you describe below are not used in mri_gtmpvc. If  you
>> are trying to get something close to what the GTM does, then use nearest
>> neighbor
>>
>> On 2/14/19 3:43 AM, Matthieu Vanhoutte wrote:
>>>            External Email - Use Caution
>>>
>>> Hi Douglas,
>>>
>>> Could you help me concerning my previous questions ?
>>>
>>> Thanks,
>>> Matthieu
>>>
>>>> Le 11 févr. 2019 à 17:37, Matthieu VANHOUTTE <matthieuvanhoutte@gmail.com> a écrit :
>>>>
>>>> Hi Douglas,
>>>>
>>>> Thanks for clarification. Why use "nearest neighbor" instead of classical "trilinear" interpolation ?
>>>>
>>>> Should it be done as well when projecting from volume to surface with mri_vol2surf ?
>>>>
>>>> Best,
>>>>
>>>> Matthieu
>>>>
>>>> On 11/02/2019 17:32, Greve, Douglas N.,Ph.D. wrote:
>>>>> It will not used trilinear interp. Try it with nearest neighbor
>>>>>
>>>>> On 2/10/19 11:55 AM, Matthieu Vanhoutte wrote:
>>>>>>             External Email - Use Caution
>>>>>>
>>>>>> Dear Douglas,
>>>>>>
>>>>>> Before using "mri_gtmpvc --psf 0 --no-tfe -- rbv" according your advice to obtain voxel-wise output rescaled without PVC correction, I have done sequentially the different steps to obtain this output. However, when comparing voxel-wise rescaled output (rbv.nii.gz) between the two methods, final values at each voxel are not the same…
>>>>>>
>>>>>> To obtain first rescaled voxel-wise output I have used sequentially these steps:
>>>>>> 1.       Concatenate transforms from PET space to gtmseg.mgz
>>>>>> 2.       Register native PET into gtmseg space (trilin. interpolation)
>>>>>> 3.       Compute mean PET inside reference regions (with regions masks from gtmseg.mgz)
>>>>>> 4.       Compute intensity normalized PET images in gtmseg space
>>>>>>
>>>>>> Doesn’t the "mri_gtmpvc --psf 0 --no-tfe -- rdv" command use these same steps ?
>>>>>>
>>>>>> Best,
>>>>>> Matthieu
>>>>>>
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