In vivo PS-OCT to detect fibrotic lung disease

Abstract

<b>Introduction:</b> Polarization sensitive optical coherence tomography (PS-OCT) provides tissue-specific contrast by assessing tissue birefringence. It enables 3D volumetric reconstruction of birefringence in the alveolar compartment and airways over ~5cm. Birefringence structures imply the presence of collagen: if detected in the alveolar compartment it indicates fibrotic tissue. Thus PS-OCT has potential to detect, quantify and follow up pulmonary fibrosis in patients with interstitial lung disease (ILD) when CT is indeterminate for presence or progression of fibrosis. <b>Methods:</b> In ILD patients prior to transbronchial cryobiopsy in-vivo bronchoscopic PS-OCT was performed. The amount of birefringence was assessed in PS-OCT images and compared to histology. <b>Results:</b> 9 ILD patients were included: hypersensitivity pneumonitis(n=3), idiopathic pulmonary fibrosis(n=2), smoking related(n=2), autoimmune related(n=1), unclassifiable(n=1). 58 segments were imaged with PS-OCT. Segments without detected birefringence showed no to minimal fibrosis in histopathology, segments with high birefringence showed clear fibrotic changes (Fig 1) [Data on quantification pending]. No adverse events occurred. <b>Conclusion:</b> Bronchoscopic PS-OCT is feasible and safe. It enables detection of fibrosis in alveolar tissue, additionally it has potential to quantify fibrosis without the need of tissue sampling. Hereby PSOCT could provide information upon fibrosis progression upon serial procedures.