Diagnostic Performance and Safety of Endobronchial Ultrasound-guided Transbronchial Mediastinal Cryobiopsy in Diagnosing Tuberculous Mediastinal Lymphadenitis: a Randomised Controlled Trial

Condition(s) studied

Investigational drug(s) / intervention(s)

EBUS-TBMC: EBUS-TBMC is a minimally invasive bronchoscopic procedure performed under moderate sedation or general anesthesia to obtain larger and more intact tissue samples from mediastinal lymph nodes compared to conventional needle aspiration. A convex probe EBUS scope is used to identify the target lymph node, and Doppler mode is employed to map vascular structures for safe puncture path planning. A dedicated puncture dilation catheter is inserted under real-time EBUS guidance to puncture the airway wall and enter the target lymph node; the needle stylet is then removed, leaving the outer sheath in place to establish a "tunnel" from the airway lumen into the lymph node parenchyma. A flexible cryoprobe is advanced through the sheath into the lymph node, with ultrasound confirmation ensuring the probe tip is positioned within the node while maintaining a safety distance of at least 5 mm from the nodal edge and any visible blood vessels. The freezing system is activated using carbon dioxide as th

EBUS-TBNA: EBUS-TBNA is a standard minimally invasive bronchoscopic procedure performed under moderate sedation or general anesthesia to obtain cytological samples from mediastinal lymph nodes. A convex probe EBUS scope is used to identify the target lymph node, and Doppler mode is employed to map vascular structures for safe puncture path planning. A dedicated 22G EBUS aspiration needle is inserted under real-time ultrasound guidance to puncture the airway wall and enter the target lymph node. Standard "to-and-fro" movements are performed approximately 30 times per pass to aspirate cellular material. For this trial, a total of five independent needle passes are performed on the same target node. The specimen from the first pass is collected directly into sterile saline for mycobacterial culture. The remaining specimens are rinsed into 10% neutral buffered formalin for cell block preparation and histopathological evaluation. The rinsing fluid from the needle and specimen container is also collect

Study summary

The goal of this clinical trial is to compare the diagnostic efficacy and safety of Endobronchial Ultrasound-guided Transbronchial Mediastinal Cryobiopsy (EBUS-TBMC) versus standard EBUS-guided Transbronchial Needle Aspiration (EBUS-TBNA) in adult patients with suspected mediastinal lymph node tuberculosis. The main questions it aims to answer are:

Does EBUS-TBMC provide a superior diagnostic yield for detecting granulomatous inflammation compared to EBUS-TBNA in the same target lymph node? Does the cryopreservation process affect the viability of Mycobacterium tuberculosis for culture, and does the larger tissue sample obtained via EBUS-TBMC enhance the sensitivity of molecular tests such as Xpert MTB/RIF? Is the safety profile of EBUS-TBMC, particularly regarding bleeding complications, comparable to that of EBUS-TBNA in this patient population? Researchers will compare the two biopsy techniques using a paired design within the same patient to see if EBUS-TBMC results in higher rates of positive pathology, microbiology, and molecular diagnoses.

Participants will:

Undergo both EBUS-TBNA and EBUS-TBMC procedures on the same mediastinal lymph node during a single bronchoscopy session, with the order of procedures randomized.

Provide blood and tissue samples for comprehensive testing, including histology, mycobacterial culture, and Xpert MTB/RIF assay.

Complete short-term (within 2 hours post-procedure) and 7-day follow-up assessments to monitor for any adverse events.

Participate in a 6-month clinical follow-up to establish a final diagnosis, which will serve as the reference standard for evaluating the diagnostic tests.

Eligibility

Primary outcome measure(s)

• Granuloma Detection Rate — Within 2 weeks post-procedure (upon completion of histopathological processing and reporting)
  The proportion of patients in whom granulomatous inflammation is detected on histopathological examination of the biopsy specimens obtained from the target mediastinal lymph node. Assessment will be performed by pathologists blinded to the biopsy technique used for each specimen.

Trial sites (1)

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