Export segment threshold

Operating system: Windows
Slicer version: 5.4.0
Expected behavior:
Actual behavior:

Hello

I am trying to manually segment brain lesions. I find that the threshold tool helps me to delineate these lesions but once I’ve chosen my thresholds and my lesion flashes blue/green I can’t add it to a segment, see it in 3D and export it. The aim is to create a segment/ROI, evaluate its volume and export it to other sequences.

Do you have an idea that could help me?

Thanks in advance