| Normal |
Regular elastin framework of the alveolar rings and less than four non-alveolar-mouth fibres in any single quadrant of the field (Figure 2D) and ≤11 cellular structures per field and/or microvessels |
| Non-specific |
No regular elastin framework of the alveolar rings and loose fibres i.e., not recognized as part of alveoli or bronchial wall |
| Increased fibres |
>4 non-alveolar-mouth fibres in at least one quadrant of the field and normal alveolar structures |
| Densely packed fibres |
Incomplete or absent alveolar structures and at least five non-alveolar-mouth fibres in any single quadrant of the field and irregular or indistinct fibre pattern i.e., not recognized as part of alveoli or bronchial wall |
| Hypercellular |
More than 11 cellular structures in one field (Figure 2C) |
| These cellular structures are visualized within the alveolar space |
| Thickened fibres |
Visual consensus of all investigators |
| Normal alveolar structures |
| Measurements show that these mean alveolar mouth fibres’ thickness is 21.9±6.17 µm, n=27. The non-thickened fibre thickness is 15.0±5.54 µm, n=111 (P<0.05) |
