Use of Narrow Band Imaging in the Diagnosis of Hypovascular Endobronchial Sarcoidosis

Role of Bronchoscopy in Diagnosis of Sarcoidosis

Sarcoidosis is a multisystem inflammatory disorder with unclear etiology and can often pose a diagnostic challenge. A tissue diagnosis is often necessary to illustrate the non-caseating granulomas on histopathology. This review aims to synthesize current evidence related to tissue diagnosis of sarcoidosis using various bronchoscopic techniques. We start by discussing standard bronchoscopic techniques which have remained the cornerstone of diagnostic workup such as bronchoalveolar lavage (BAL), endobronchial biopsy (EBB), conventional transbronchial needle aspiration (cTBNA) and transbronchial lung biopsy (TBLB) followed by newer modalities that incorporate real-time image guidance using endobronchial and endoscopic ultrasound. Although BAL, EBB, and TBLB have been employed as a diagnostic tool for several decades, their sensitivity and diagnostic yield is inferior to ultrasound-based endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). More recently, convincing evidence has also emerged to support the diagnostic accuracy and tissue yield of transbronchial lung cryobiopsy which will also be discussed in this review. These advances in bronchoscopic equipment and techniques over the last 2 decades have made it possible to obtain tissue samples using minimally invasive techniques thus avoiding invasive open lung biopsy and the risks that inherently follow. Up-to-date knowledge of these modalities is imperative for ensuring evidence-based medicine and improving patient-centric outcomes.

High-Definition Videobronchoscopy for the Diagnosis of Airway Involvement in Sarcoidosis: The Enhance Sarcoidosis Multicenter Study

BACKGROUND

The ability of high-definition (HD) videobronchoscopy to detect airway involvement in sarcoidosis has not been evaluated previously.

RESEARCH QUESTION

What is the role of HD videobronchoscopy in the identification of sarcoidosis-associated airway abnormalities (AAs)? What are the patterns of AAs more commonly observed and more frequently associated with the detection of granulomas in endobronchial biopsy (EBB)?

STUDY DESIGN AND METHODS

In this prospective international multicenter cohort study, consecutive patients with suspected sarcoidosis underwent airway inspection with an HD videobronchoscope and EBB using a standardized workflow. AAs were classified according to six patterns defined a priori: nodularity, cobblestoning, thickening, plaque, increased vascularity, and miscellaneous. We assessed diagnostic yield of EBB, prevalence of AAs, and interobserver agreement for different patterns of AAs.

RESULTS

AAs were identified in 64 of 134 patients with sarcoidosis (47.8%), with nodularity (n = 23 [17.2%]), plaque (n = 19 [14.2%]), and increased vascularity (n = 19 [14.2%]) being the most prevalent. The diagnostic yield of EBB was 36.6%. AAs were significantly more prevalent in patients with than in those without nonnecrotizing granulomas on EBB (67.4% vs 36.5%; P = .001). Likewise, parenchymal disease on CT scan imaging was significantly more common in patients with than in those without nonnecrotizing granulomas on EBB (79.6% vs 54.1%; P = .003). On a per-lesion analysis, nonnecrotizing granulomas were seen especially in EBB samples obtained from areas of cobblestoning (9/10 [90%]) and nodularity (17/29 [58.6%]). The overall diagnostic yield of random EBB was low (31/134 [23.1%]). The interobserver agreement for the different patterns of AA was fair (Fleiss κ = 0.34).

INTERPRETATION

In a population with a large prevalence of White Europeans, HD videobronchoscopy detected AAs in approximately one-half of patients with sarcoidosis. The diagnostic yield of EBB was higher in patients with parenchymal involvement on CT scan imaging and in those with AAs, especially if manifesting as cobblestoning and nodularity.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT4743596; URL: www.

CLINICALTRIALS

gov.

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 (χ 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 (Κ=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.