Optical coherence tomography for human airway wall layer identification and quantification

Abstract

INTRODUCTION Several airway diseases are characterized by airway remodeling. The current imaging techniques to assess airway wall layers/airway remodeling have limitations. Optical coherence tomography (OCT) is a minimal invasive, high-resolution optical imaging technique which generates real-time, high-detailed images of airway segments. How OCT images relates to histology is largely unknown. AIM Ex-vivo identification and quantification of human airway wall layers by OCT and correlate this to histology. METHODS In 5 lobectomy specimen 13 airways were dissected, marked with suture needles and imaged by OCT. Histology sections were stained with hematoxylin and eosin to visualize airway wall layers and desmin to identify the airway smooth muscle layer. Airway wall thickness was measured by tracing the luminal perimeter (LA) and airway smooth muscle outer perimeter (TA). Airway wall area (WA (mm2)) and airway wall area percentage (WA%) for both OCT and histology where calculated by WA=TA-LA and WA%=WA/TA x100% respectively. RESULTS 51 matched OCT- histology airway cross sections were analyzed. The following separate airway wall layers were identified on OCT imaging; epithelium, basal membrane, lamina propria surrounded by smooth muscle, glands, vessels and cartilage. WA and the WA% measured by OCT correlated with histology (N=51; R 0.76 95% CI 0.61-0.86, p CONCLUSIONS Ex-vivo OCT imaging correlates well with histopathology both for identification of airway wall layers and quantification of airway wall thickness. IMPLICATIONS OCT imaging might qualify as the imaging technique of choice to assess airway wall remodelling.