Dear Freesurfer's experts, Could anyone please explain me the difference I got with command line in below mail ?
Best regards, Matthieu 2016-08-12 12:07 GMT+02:00 Matthieu Vanhoutte <matthieuvanhou...@gmail.com>: > Dear experts, > > I am in trouble with two ways of computing mean intensity with > mri_segstats. > > First I have used on .annot files with three different labels inside > (SegId 1 to 3) : > > *mri_segstats --annot fsaverage lh cache.th23.pos.sig.ocn.annot --i > lh.PET.fsaverage.sm10.mgh --sum lh.pet.sum* > > which give me those results: > # ColHeaders Index SegId NVertices Area_mm2 StructName Mean StdDev Min > Max Range > 1 1 27805 14182.6 cluster-001 8.8194 > 1.4351 6.2105 14.2947 8.0842 > 2 2 2321 1047.3 cluster-002 10.3661 > 1.0848 8.8375 12.9317 4.0942 > 3 3 552 313.1 cluster3 10.3365 > 0.4711 9.3719 11.8694 2.4975 > > Second I have created on .label files containing the three segmented > labels (SegId 1 to 3) and used this label with mri_segstats: > > *mri_segstats --slabel fsaverage lh lh.th23.cluster.thresh1.3.label --i > lh.PET.fsaverage.sm10.mgh --excludeid 0 --sum lh.pet.label.sum * > > which give me those results: > *# ColHeaders Index SegId NVertices Area_mm2 StructName Mean StdDev Min > Max Range * > * 1 1 30678 15542.9 Seg0001 8.9637 1.4701 6.2105 > 14.2947 8.0842 * > > I verified if I obtained the same results with the two ways (.annot or > .label) and everything is fine comparing NVertices, Area_mm2 but Mean in > first way gives me (8.8194+10.3661+10.3365)/3 = 9.84066 and with .label > file Mean = 8.9637. > > Did I have miss anything and how is computed mean intensity ? > > Many thanks in advance. > > Best regards, > Matthieu >
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