Cone beam CT is essential for worthwhile navigation bronchoscopy of small lung nodules

Abstract

<b>Introduction:</b> Electromagnetic navigation bronchoscopy (ENB) allows lung lesions to be reached quickly and safely, but accuracy of biopsies is hampered by CT-to-body divergence, which can be corrected by cone beam CT (CBCT). We examine the impact of CBCT on ENB safety and positive diagnosis (PD). <b>Methods:</b> A single institution retrospective observational study of ENB and CBCT on pneumothorax and PD rates. No radial EBUS, fluoroscopy or rapid on site evaluation was used. PD includes only confirmed malignant and firm benign histologies (eg granulomatous inflammation, harmatoma), but excludes atypical histology, nondiagnostic and nonspecific features (eg fibrosis, inflammation). <b>Results:</b> From Jan 2015-22, 492 patients (mean age 68.4) underwent ENB biopsy of 572 lung lesions. 101 patients with 114 lesions underwent ENB without CBCT (Gp1) and 391 patients with 458 lesions underwent CBCT-guided ENB (Gp2). The first 20 patients of each group were excluded from analysis as part of the learning curve. The mean size of the nodules was 21.6mm (27.5mm Gp1 vs 20.3mm Gp2). 9 patients out of 452 (2.0%) developed a pneumothorax. CBCT reduced the pneumothorax rate by 5.5 fold (6.2% Gp1 vs 1.1% Gp2, p&lt;0.01). The overall PD rate was 65.7% (55.0% Gp1 vs 68.0% Gp2, p=0.02). The PD rate for lesions ≥2cm increased by 5.1% with the use of CBCT (72.2% Gp1 vs 75.9% Gp2, p=0.59), whereas for lesions &lt;2cm, the PD rate increased significantly by 113.2% (29.0% Gp1 vs 61.9% Gp2, p&lt;0.01). <b>Discussion:</b> CBCT increases the safety and PD rate of ENB. ENB without CBCT for lesions &lt;2cm has an unacceptably low PD rate. CBCT significantly improved PD rate by two fold. For ENB to be worthwhile for small lesions, CBCT is an essential adjunct.