Instant diagnosing interstitial lung disease using higher harmonic generation microscopy

Abstract

<b>Introduction:</b> Lung biopsy in ILD comes with considerable morbidity and includes the risk of sampling error. Higher harmonic generation (HHG) microscopy is a laser-based imaging technique, that provides real-time images of tissue with submicron resolution without the need for processing or staining tissue. <b>Methods:</b> ILD patients undergoing bronchoscopic lung cryobiopsy were included. Following tissue extraction, unprocessed lung tissue was imaged with a mobile HHG microscope. Subsequently, biopsies were processed according to standard pathological practice and matched with HHG images. <b>Results:</b> 21 matching HHG images and related cryobiopsies were obtained from 6 patients (hypersensitivity pneumonitis n=2, idiopathic pulmonary fibrosis n=1, auto-immune related ILD n=1, smoking related ILD n=1, unclassifiable n=1). Discriminating ILD characteristics were identified based on alveolar collagen deposition, cellular infiltrates, and presence of specific cells, i.e. multinucleated giant cells, and macrophages (Figure 1). <b>Conclusion:</b> HHG microscopy can instantly identify histological characteristics in ILD patients without the need of tissue staining or processing. <b>Implication:</b> HHG may reduce the need for the number of cryobiopsy samples. Bronchoscopic HHG endomicroscopy is currently under development with the potential to function as a minimally invasive bronchoscopic optical biopsy tool.