Evaluation of diagnostic accuracy and molecular adequacy between conventional endobronchial ultrasound, contrast-enhanced endobronchial ultrasound and elastography for hilar and mediastinal lymphadenopathies: a retrospective observational study.

BACKGROUND: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a cornerstone for mediastinal staging in lung cancer; however, sampling of bulky or necrotic lymph nodes remains challenging, often leading to inadequate tissue for molecular analysis. This study aimed to compare the diagnostic accuracy and molecular adequacy of conventional EBUS, contrast-enhanced EBUS (CE-EBUS) and EBUS elastography in patients with hilar and mediastinal lymphadenopathies.

METHODS: We conducted a retrospective, single-center study from April 2021 until January 2025, including 74 consecutive patients with mediastinal or hilar lymphadenopathies suspicious for malignancy on computed tomography (CT) and/or positron emission tomography-CT using 18F-fluorodeoxyglucose (18F-FDG PET-CT) [maximum standardized uptake value (SUVmax) >2.5]. Patients with suspected autoimmune or lymphoproliferative disease were excluded. All lymph nodes were bulky (>30 mm) and/or showed radiologic necrosis. All patients were distributed into three groups based on the technique used for lymph node evaluation: Conventional EBUS (n=26), CE-EBUS (n=23), and elastography (n=25). CE-EBUS was performed following the intravenous administration of 4.8 mL sulphur hexafluoride. Final diagnosis was based on histopathology and clinical-radiological follow-up in negative cases. Molecular adequacy was defined as the availability of sufficient viable material for standard molecular analyses. Diagnostic accuracy and molecular adequacy were compared across techniques, including a subgroup analysis focusing on bulky or necrotic lymph nodes.

RESULTS: Baseline demographic, clinical, radiologic, and metabolic characteristics were comparable across groups. Overall diagnostic accuracy did not differ significantly among techniques. In analyses adjusted for bulky and necrotic lymphadenopathy, CE-EBUS was associated with higher molecular adequacy compared with conventional EBUS, while no statistically significant differences were observed between conventional EBUS and elastography.

CONCLUSIONS: CE-EBUS seems to improve diagnostic and molecular yield, particularly in bulky or necrotic lymph nodes, by identifying vital tissue. Elastography provides complementary stiffness information, enhancing overall lymph node characterization. These results could expand upon prior evidence supporting CE-EBUS utility in mediastinal staging.