Print

Print


Hello,

I'm trying to run shape analysis using First.

Using bias-corrected T1 files, I have applied the following steps:

 for f in old_*_T1_biascorr.nii.gz; do run_first_all -i $f -o "$f"; done

cat*.logs/*.e*

I checked both the registrations and the segmentations on a subject by subject basis using overlays in fslview and looked at overview with slicesdir method. They both seem acceptable, for the segmentation my focus was on checking the larger structures of interest.

concat_bvars command with controls first and then patients

The GLM design is attached.

first_utils --usebvars --vertexAnalysis -i old_to_mci_L_Hipp.bvars -d old1_mci2.mat -o old1_mci2_L_Hipp_mni --useReconMNI  -v >& old1_mci2_L_Hipp_output.txt

randomise -i old1_mci2_L_Hipp - m old1_mci2_L_Hipp_mask -o old1_mci2_L_Hipp_rand -d old1_mci2.mat -t old1_mci2.con -f old1_mci2.fts -D -T n 500
(At the moment, n=14 per group hence the smaller number of permutations.)

first3Dview old1_mci2_L_Hipp_mni_mask  old1_mci2_L_Hipp_rand_corrp_tstat1

When I open the 3D viewer in fslview, the following error is displayed in the terminal:

80
ERROR: In /build/vtk-BebTbT/vtk-5.8.0/Graphics/vtkDecimatePro.cxx, line 163
vtkDecimatePro (0x46fd1be0): No data to decimate!

ERROR: In /build/vtk-BebTbT/vtk-5.8.0/Graphics/vtkSmoothPolyDataFilter.cxx, line 211
vtkSmoothPolyDataFilter (0x43866130): No data to smooth!

In the 3Dviewer I can see the left hippocampus perfectly displayed in solid blue (i.e., no indication of any stats). I have separately run volumetric analysis and there is no significant volume difference between the groups. Perhaps this is why there are no colour changes in the shape? However, I don't understand the meaning of the error message and whether it relates to the shape analysis. Following a previous thread, I have tried to adjust the figure (intensity ?) shown beside the clipping tick box but it makes no difference and I cannot change the intensity values shown beside the co-ordinates. I'm using fslview version 4.01.

Additionally, I am unsure as to whether I set up the GLM correctly. I have attached a png of the design. The wiki states that First ignores the group column but I couldn't figure out how to set up contrasts without assigning group membership. (In fact, rather than the attached design, I'd like to do a one-sided t-test  testing only old>mci, but I was stumped.)

If you can help regarding the first3Dview error and the GLM query (they may be related?), I would greatly appreciate it.

Many thanks,

Therese


########################################################################

To unsubscribe from the FSL list, click the following link:
https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=FSL&A=1