Use of Narrow Band Imaging to Guide Endobronchial Biopsy for Suspected Sarcoidosis.

Background: Diagnosis of sarcoidosis often involves endobronchial biopsy (EBB), but studies have shown varying yields for EBB in suspected sarcoidosis, partly due to differences in identifying abnormal mucosa under white light (WL). Narrow band imaging (NBI) may assist in the visualization of abnormal mucosa, but its role in sarcoidosis remains to be characterized.

Methods: Individuals referred for suspected sarcoidosis were considered for enrollment. Bronchoscopy with both WL and NBI was conducted, followed by EBB. The main objectives were to characterize NBI abnormalities in this patient population and determine the incremental yield of NBI-directed EBB.

Results: In our cohort of 100 suspected sarcoidosis patients (66% male, median age 42), 88 were diagnosed with sarcoidosis, through cytopathology (n=78) or clinical evaluation (n=10). NBI high-grade lesions were more common than WL high-grade lesions (58% vs. 27%, difference 31%, 95% CI 18.3-42.5% P<0.001). High-grade WL EBB were more likely to be positive than low-grade WL biopsies [20/31 (65%) vs. 20/91 (22%), odds ratio (OR) 6.5, 95% CI 2.7-15.6, P<0.01]). Conversely, high-grade NBI lesions were no more likely to be positive than low-grade NBI lesions [23/63 (37%) vs. 17/59, (29%), OR 1.42, 95% CI 0.66-3.0, P=0.366]. EBB positivity and false-negative EBUS-TBNA were more common in patients with Scadding stage 2 or greater, suggesting that the chest radiography stage may help select patients more likely to benefit from adjunctive EBB.

Conclusion: NBI abnormalities are common in patients with sarcoidosis, but unlike WL abnormalities, do not predict the finding of granulomatous inflammation on EBB. The chest radiography stage may be useful to identify patients more likely to benefit from EBB in addition to EBUS-TBNA.