Operating system: macOS Big Sur version 11.2.2
Slicer version: 4.11.20200930

Hi, I’m trying to understand why the number of voxels computed by scalar volume statistics plugin is much different from the number of voxels computed by labelmap statistics plugin. I would like to compute the mean activity inside each VOI, so I need to multiply the mean value by the correspondent number of voxels… which one should I use, scalar or labelmap-computed number?
If anyone could help me I would be very grateful :smiley:

The difference is most likely due to that the scalar volume plugin only considers that region of the segmentation that overlaps with the chosen scalar volume.