Soft-tissue segmentation: advice needed

Hello,

I would like to get your opinion on an approach I am currently using to refine the segmentation of soft tissues in a head MRI.

I used TotalSegmentator (MR) to automatically segment the soft tissues, particularly fat and muscle. I then defined an external 3 mm layer from the outer surface of the head, which I am currently assuming represents the dermal/skin layer. The remaining soft-tissue regions that are not classified as fat or muscle were grouped into a fourth region that I called “Others”.

This gives me four distinct material regions:

  • Skin/dermal layer: 3 mm external layer

  • Fat

  • Muscle

  • Others

This is part of a research project focused on hearing protection and the study of sound propagation through the tissues of the head. The objective is mainly technological/modeling-oriented, rather than clinical or anatomical diagnosis.

My main question is whether this level of differentiation seems relevant for an acoustic/biomechanical model. In particular:

  • Is it reasonable to consider four distinct materials?

  • Would it be appropriate to interpret the “Others” region as mainly epidermis/other superficial soft tissues, or would you recommend treating it differently?

  • More generally, does this segmentation approach seem physically meaningful for studying sound propagation through the soft tissues?

I would greatly appreciate any feedback or recommendations on how you would approach this segmentation.