Local threshold on ROI volume

Hi,
I’m a new user of 3Dslicer Mac version 5.2.1.

I’m currently working on paralumbar muscles in MRI, particularly their volumes and fatty degeneration:

  1. Once the volume of a muscle is achieved, is it possible to perform a local threshold on the total volume? In order to separate the muscle (black) from the fat (white) into only two distinct elements (ie. binary solution only black or white).
  2. Once the volume of a muscle is achieved, is it possible to perform a local threshold on a ROI within the volume, for a given slice?
  3. More generally, is it possible to perform a local threshold on a predefined area (e.g. on a CSA of the muscle), and not on the whole axial slice section?

Thanks