Table 2: Categories for the classification of high frequency ultrasound images [4].

CategoryDescription

0Normal scan—no sign of PU development
Subgroup 1Pockets of subcutaneous oedema
Subgroup 2Strips of dermal damage and increased subcutaneous damage
Subgroup 3Subepidermal inflammation, strips of dermal damage, and major subcutaneous damage
UngradedUnable to assess due to poor image quality