Feasibility study of normal and septic tracheal imaging using optical coherence tomography.

BACKGROUND AND OBJECTIVES Optical coherence tomography (OCT) is an imaging technology that may be adapted for use with flexible fiberoptic bronchoscopy, potentially allowing it to play an important role in pulmonary diagnostics. The goal of this study was to evaluate the feasibility of OCT to image tracheal pathology. STUDY DESIGN/MATERIALS AND METHODS Tracheas were harvested from normal and septic New Zealand White rabbits and imaged using OCT. Two delivery devices were employed. One was a moving stage with an objective lens and collimator, the other a linear scanning flexible fiberoptic catheter using a GRIN lens and prism for endoscopic OCT. After OCT images were obtained from normal and septic tracheas, the excised tissues were prepared for standard histologic examination. Areas imaged by OCT were compared with corresponding histology slides. RESULTS OCT images demonstrated in detail tracheal sub-surface structures such as the epithelium, lamina propria, submucosa, and cartilage. The appearance of structures imaged by OCT corresponded very well with histologic pictures obtained by light microscopy. The OCT images from septic tracheas showed marked swelling of the mucosal and submucosal layers. Such pathology was equally imaged by either the moving stage or fiberoptic catheter for endoscopic OCT. CONCLUSIONS OCT images of the trachea can distinguish many sub-surface structural features usually requiring biopsy and light microscopy for visualization. Marked differences between normal and septic trachea were apparent in OCT images. In the future, OCT may be a valuable tool for evaluating tracheal pathology in situ with high image resolution.