Endobronchial polarization sensitive optical coherence tomography for airway smooth muscle detection in pulmonary disease

<bold>Introduction:</bold> Biopsies are currently the gold standard to assess airway wall remodeling. In vivo endobronchial polarization sensitive optical coherence tomography (EB-PS-OCT) is a high resolution (10 μm), bronchoscopic imaging technique that provides tissue specific contrast to detect and quantify airway smooth muscle (ASM). <bold>Aim:</bold> Assess ASM changes with EB-PS-OCT in diseased and healthy airways. <bold>Methods:</bold> Interstitial lung disease (ILD) and asthma patients, and healthy volunteers underwent EB-PS-OCT imaging of middle and right lower lobe airways. ASM percentage was automatically quantified by segmenting birefringent areas with constant circumferential optic axis orientation. <bold>Results:</bold> 17 patients were included (14 ILD, 1 asthma, 2 healthy volunteers). EB-PS-OCT enabled ASM segmentation and quantification in 26 diseased airways and 6 healthy airways. Preliminary results show an increased ASM median percentage in both ILD and asthmatic airways compared to healthy controls (Fig 1). <bold>Conclusion:</bold> EB-PS-OCT is a minimally invasive technique to quantify ASM thickness in healthy and diseased airways, providing new insight in airway remodelling in both ILD and asthma. Inclusion of more asthma patients and healthy controls will allow validation of these preliminary results. <fig><object-id>erj;64/suppl_68/OA5471/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>