the problem of using VBM and DARTEL in process images

Submitted by fish on

YAN Chao-Gan

Wed, 01/01/2014 - 16:26

Hi,

Seems you applied a mask when performing two-sample t-test on gray matter files (swc1*)? How did you generate that mask -- which seems a little bigger?

Best,

Chao-Gan

严老师:

               我在用这两种方法时都没有使用mask,因为有论坛说无论VBM还是DARTEL,做出来的voxel是1.5x1.5x1.5mm,而spm或者rest slice viewer的大脑模板好像是1x1x1mm,是否我需要先把two-sample t test做出来的图先reslice为1x1x1mm,再使用spm或者rest默认的mask,还是先在two-sample t test中使用mask,再reslice?我可能有些概念表述的不是很清楚,不知道您是否能理解?

你好!

如果没有加mask,脑外只要有值,就会进入统计(spm也会自动生成这样的mask),所以看起来图会比脑更大。

你可以施加一个mask,如果你的mask (1x1x1)与数据(1.5x1.5x1.5)不一致,你可以先将mask reslice到同你数据一样的精度(REST->Utilities->Reslice)。你在统计中,应用这个重采样之后的mask就可以了。

祝一切顺利!

超赣

 

Dear Doctor YAN:

                          No matter I used VBM and DARTEL processing 3D-T1 images, I found that after the two-sample t-test, the voxels is larger than the brain module in SPM or REST, just like the picture below. I displayed the images before I preocessed them and set the  Gaussian FWHM 8 mm. I do not know why.