Utility of Narrow-band Imaging Bronchoscopy in the Diagnosis of Endobronchial Sarcoidosis

Background:There are few reports on the utility of bronchoscopic narrow-band imaging (NBI) for visualizing endobronchial abnormalities in sarcoidosis. Our primary objective was to compare the sensitivity of finding endobronchial abnormality using NBI versus white light bronchoscopy (WLB) in patients with sarcoidosis. The secondary aim was to evaluate the sensitivity of NBI in diagnosing endobronchial sarcoidosis against a reference standard of positive endobronchial biopsy (EBB).Methods:We retrospectively included subjects with sarcoidosis, where we sequentially recorded WLB and NBI videos to visualize the endobronchial mucosa. We collected data on the demographic findings, sarcoidosis stage, and the histopathological findings of transbronchial needle aspiration, EBB, and transbronchial lung biopsy. Three experienced bronchoscopists viewed the video recordings and noted the abnormalities of the airway mucosa separately on WLB and NBI.Results:We included 28 subjects (mean age, 42.9 y; 53.6% men; 14 each, stages 1 and 2) with a final diagnosis of sarcoidosis. Granulomas were detected on EBB in 11 (39.3%) subjects. We identified endobronchial nodules in 10 and 15 subjects on WLB and NBI. The sensitivity of finding endobronchial abnormality using WLB and NBI was 35.7% (10/28) and 53.6% (15/28), respectively (chi 2=1.77, df=1, P=0.18). The sensitivity of NBI in diagnosing endobronchial sarcoidosis against a positive EBB was 63.6% (7/11 subjects). There was excellent agreement (Kappa=0.86) for detecting nodules on NBI among the 3 observers.Conclusion:NBI might allow the identification of additional abnormalities not detected on WLB in sarcoidosis. Larger studies are required to confirm our observations.