191 Pattern recognition in pulmonary AdC; a modified classification Figure 11. The relation between volume (red line) and surface (blue line) is shown for boxes of different shapes involving progressive reduction in size of one rib and similar increase of a second rib while the third rib remained unchanged. A smaller box requires less surface. As during iatrogenic collapse, the alveolar surface does not change, the relative excess of surface is shown by the green arrow. The effect on the box surfaces and volumes with progressive decrease in size of one rib and increase in size of another rib is shown in Figure 11. According to the model’s prediction, near maximal collapse, there is an estimated decrease in surface area of approximately 15-20% and a decrease in volume of 95100%. This decrease in surface and volume is similar across boxes of sizes 200, 300, and 400 µm, indicating that this reduction is independent of the original size of the box, i.e., alveolar size. To quantify the maximal collapse of pulmonary parenchyma, a sample without malignancy and virtual absence of air was used, where the pneumocytes type I of an alveolar wall practically touch the pneumocytes of the opposing alveolar wall. The measurements revealed that 12 alveolar wall cross sections fit in nearly complete iatrogenic collapsed normal lung parenchyma in a length of 200 μm (the size of an average alveolus) (figures 12 A and B), as well as that the alveolar septa showed an undulated appearance. In adenocarcinoma resections with lepidic growth, a mean of 4.8 (range 3 to 7) and 4.3 (range 3 to 6) alveolar walls were measured in Milan and Amsterdam cohort, respectively (figures 12 C and D). 14
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