The 2D tree starts at the "Root" node, and finishes with "Frames" nodes. Each file that you read in Baby SliceO contains one or, sometimes, multiple images. Each images is a "frame". The root and the frames are both a "class" of nodes.
The root and the frames are always present in the database tree. But in between, you can add other classes.
The classes "Study" and "Series" are used to sort the tree in patient/study/series/image hierarchy.
For example if we load 5 files in Baby SliceO, each having 1 image and with the following parameters:
If we create different combinations of trees using the Study and Series classes on top of the default Root and Frames, we will have the following trees:
By default, the tree contains the root, study, series and the frame classes.