The min/max/etc are the voxel wise measures. When you use --accumulate, it sums all the voxels but does not divide by the number of voxels, so you get a number much larger than any one voxel
doug

On 9/3/14 9:44 PM, SHAHIN NASR wrote:

Hi Surfers,

    I want to measure the average amount of myelinations within my ROI(s),

    I have already generated my myelination maps on surfaces (e.g. lh.myelin_ProjFrac0p5.nii ). Then I used mri_segstats as below:

mri_segstats --i lh.myelin_ProjFrac0p5.nii --slabel SBJ_001 lh lh.V1 --sum V1_Stats.txt --accumulate

but the numbers don't make any sense. For instance:

# ColHeaders Index SegId NVertices Area_mm2 StructName Mean StdDev Min Max Range
1   0    125261    82573.4 Seg0000 110280.4453     0.2922    -5.5000    51.0000    56.5000
2   1      1138      764.8 Seg0001   941.0988     0.1572     0.2675     1.4203     1.1527

How can mean=941.0988 when the max=1.4203 ???

Regards

--
Shahin Nasr

PhD in Cognitive Neuroscience
Martinos Imaging Center, MGH
Harvard Medical School
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