Diagnostic yield of different ultrasound-guided biopsy procedures in mediastinal lymphadenopathy: an accessibility-based triage pathway

Abstract

Background
Mediastinal lymph node evaluation can be performed using several techniques. Imaging modalities such as positron emission tomography–computed tomography (PET‑CT), magnetic resonance imaging (MRI), and computed tomography (CT) provide relatively high sensitivity in detecting mediastinal disease. Mediastinoscopy remains the gold standard for diagnosing mediastinal lesions, though it carries intraoperative and postoperative risks. Ultrasound (US) offers two distinct advantages: it can be integrated into endoscopic procedures and allows real‑time sampling of mediastinal lesions.


Aim
To evaluate the diagnostic yield of three ultrasound guided biopsy procedures applied along an accessibility-based triage pathway in patients with mediastinal lymphadenopathy,


Methods

This prospective, interventional, exploratory observational study that was conducted at the chest diseases department faculty of Medicine, Cairo University. Seventy-nine consecutively enrolled adult patients with CT-confirmed mediastinal were allocated to one of three biopsy modalities based on anatomical accessibility (not by randomization): CUSB (
n
 = 24, accessible cervical nodes), TUSB (
n
 = 31, accessible parasternal mediastinal nodes), or CP-EBUS (
n
 = 24, no nodes accessible by surface ultrasound).



Results
A definitive diagnosis was achieved in 74 of 79 cases; 5 required further surgical intervention. Within each accessibility-defined subset: CUSB sensitivity 95.83% (95% CI: 79.8–99.3%); TUSB sensitivity 100% (95% CI: 89.0-100%); CP-EBUS sensitivity 83.33% (95% CI: 64.1–93.3%). For malignancy diagnosis across all modalities: sensitivity 92.31% (95% CI: 83.2–96.7%), specificity 100%, PPV 100%, NPV 73.68% (95% CI: 51.2–88.2%), overall accuracy 93.67% (95% CI: 86.0-97.3%). These results represent a modality specific yields within distinct patient subsets and should not be interpreted as head-to-head performance comparisons.


Conclusions
In this exploratory study, ultrasound-guided biopsy demonstrated high diagnostic yield in the three modalities. These findings are hypothesis-generating;