Feasibility study of a novel synchrotron-based imaging method to assess bleomycin-induced pulmonary fibrosis progression in mice in vivo

<bold>Background:</bold> Current imaging techniques lack sufficient resolution to detect anatomical changes in the lung parenchyma in animal models <italic>in vivo</italic>. We have developed a synchrotron-based x-ray diffraction enhance imaging (DEI)-based multiple-image radiography (MIR) method to follow the progression over time of alveolar damage in mice <italic>in vivo</italic>. This technique provides information on lung x-ray scattering; and the amount of scattering is proportional to the number of air/tissue interfaces. Thus, the larger the amount of scattering, the more air-filled alveoli exist in the parenchyma. <bold>Methods:</bold> Using DEI-MIR we optimized <italic>in vivo</italic> imaging of lung damage progression in C57BL/6 mice after intratracheal administration of bleomycin (BLM) (2.0 unit/kg, n=16), or phosphate-buffered saline (PBS) administration was used as control (n=6). At the end of the experimental period, we sacrificed mice and compared synchrotron images to histology. <bold>Results:</bold> The results show that the scattering signal intensities were significantly decreased after 2 weeks after BLM challenge in the mice, with significant recovery at week 4 (Fig 1). The parenchyma damage was confirmed by histological studies at the same time points. <bold>Summary:</bold> DEI-MIR provides a non-invasive quantitative assessment tool for longitudinal studies of lung damage progression. <fig><object-id>erj;64/suppl_68/PA3368/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>