Number of detections in parent object not always the sum of number of detections in child objects

Hello everyone,

I am currently wondering why the summation of the DAPI detected cells via stardist in the ventricular systems (1157), fiber tracts (13868), and basic cell groups and regions (160543) objects in the attached images does not equal the number of DAPI detected cells in the root parent (176182) object. This phenomenon occurs for some other parent objects (lateral ventricle) as well in this particular example. I am wondering if this is simply due to ABBA’s hierarchy not including some areas such as some ventricular space as child objects or if there is a different issue. My goal is to create histograms for regions of interest but this is posing an issue since I do not know the exact cause. If anyone has ideas as to why this may be happening, please let me know.

Thank you,

Taz

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One reason this could be is that some super-regions have more voxels then the sum of their children, because there are some ‘inter-region’ areas that are considered part of the parent but none of the children.