In reply to the question of Carles Soriano, I would like to ask you SPMers if it is ok to reslice (with Reslice option of Coregister) the avgT1_Dartel_IXI550_MNI152.nii to the space defined by one image of the data (in my case it will have size 256x256x160 and voxel size 1x1x1mm3) and then use the resliced template in VBM8 procedure to perform segmentation? The same can be done with the TPM.nii?

If this is ok, which method is better to use: NN, Trilinear or higher degree B-spline interpolation?

Finally, is this apporach is ok, where in the VBM framework is possible to select the new resliced MNI template? In regard to the TPM you can directly select it in the "Estimation Options" but not the Dartel template... you can only select "High-dimensional Dartel" as the "Spatial normalization" method in the "Extended options".

Thanks in advance.

Joćo Duarte


On Thu, Nov 25, 2010 at 5:50 PM, MCLAREN, Donald <[log in to unmask]> wrote:
As far as I know, and have used, there is no reason not to change the 1.5mm^3 to 1mm^3. In non-human primates, I believe we used either .5mm^3 or 1mm^3. The one caveat is processing time.

If you have 8 1.5mm^3 voxels, you will have 27 1mm^3 voxels, so the processing time with increase substantially.

Best Regards, Donald McLaren
=================
D.G. McLaren, Ph.D.
Postdoctoral Research Fellow, GRECC, Bedford VA
Research Fellow, Department of Neurology, Massachusetts General Hospital and Harvard Medical School
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On Thu, Nov 25, 2010 at 4:29 AM, SORIANO MAS, CARLES <[log in to unmask]> wrote:
Dear SPMers,

default voxel size for normalization (Dartel) with the VBM8 toolbox seems to be 1.5 mm3. Is it a good idea to increase it to 1mm3, especially considering that raw voxel size is 1mm3? Which is the best way to change this default parameter?

Best regards,

Carles Soriano,
Barcelona.