How to change segmentation sizes?

I’m having trouble with the segmentation size in Slicer. The size of the CT I am working on is 400x400x296, but the segmentation is 252x351x270. I tried to create other segmentations and each time the size is different and does not correspond to the original CT size.
Visually, segmentation overlaps perfectly with CT, but I also need the segmentation sizes to match the size of the CT.
Slicer version 5.2.1

Is it possible to change the segmentation size and if so, how?

I will be very grateful for your help.