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Le jeu. 14 févr. 2019 à 18:31, Greve, Douglas N.,Ph.D. < DGREVE@mgh.harvard.edu> a écrit :
On 2/14/19 12:16 PM, Matthieu VANHOUTTE wrote:
External Email - Use CautionHi 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.
Thank you I will look into the paper, I was wondering how not to loose the gtmseg resolution ?
Concerning RBV PVC in which order and what type of interpolation are used since PVE corrected output is on gtmseg_space ?
And what about the interpolation method to use when projecting PVE corrected PET on surface ?
I usually use nearest neighbor to avoid interpolation
Should you precise this on PETSurfer wiki since on the mri_vol2surf command trilinear interpolation is used by default ?
Best.
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 CautionHi 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 > > _______________________________________________ > Freesurfer mailing list > Freesurfer@nmr.mgh.harvard.edu > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
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