A novel approach for automated alveolar morphometry using synchrotron X-ray microtomography in intact rat lung

Abstract

<b>Background:</b> Morphometric changes in the lung alveolar and acinar structures induced by breathing remain largely unknown. This is due to a lack of non-destructive techniques allowing quantitative morphometry of the peripheral lung. Here, we propose a new method to quantify the morphometry of the distal lung in small animals. <b>Methods:</b> Using synchrotron radiation phase-contrast X-ray tomography, we acquired 3D images of intact adult rat lungs with a spatial resolution of 3 µm, immediately post-mortem at 0 and 6 cmH2O airway pressure (Paw). We used an « r- tubular neighborhood » of the solid phase, that is the part of the empty phase which is located at distance less than r from the solid phase, to assess the underlying geometrical structure. <b>Results:</b> Figure 1 represents a segmented view of the image obtained after preprocessing. We found a mean alveolar diameter of 55 and 78 µm at 0 and 6 cmH2O Paw, respectively, in a representative rat. <b>Conclusions:</b> Our data show that this novel approach is feasible and allows measuring the local size of alveoli in a robust way, and to investigate its dependence on Paw.