Electromagnetic navigation bronchoscopy (ENB) has been developed as a novel ancillary tool for the bronchoscopic diagnosis of pulmonary nodules. Despite successful navigation in 90% of patients, ENB diagnostic yield does not generally exceed 70%. We sought to determine whether the presence of a bronchus sign on CT imaging conditions diagnostic yield of ENB and might account for the discrepancy between successful navigation and diagnostic yield.

We conducted a prospective, single-center study of ENB in 51 consecutive patients with pulmonary nodules. ENB was chosen as the least invasive diagnostic technique in patients with a high surgical risk, suspected metastatic disease, or advanced-stage disease, or in those who demanded a preoperative diagnosis prior to undergoing curative resection. We studied patient and technical variables that might condition diagnostic yield, including size, cause, location, distance to the pleural surface, and fluorodeoxyglucose uptake of a given nodule; the presence of a bronchus sign on CT imaging; registration point divergence; and the minimum distance from the tip of the locatable guide to the nodule measured during the procedure.

The diagnostic yield of ENB was 67% (34/51). The sensitivity and specificity of ENB for malignancy in this study were 71% and 100%, respectively. ENB was diagnostic in 79% (30/38) patients with a bronchus sign on CT imaging but only in 4/13 (31%) with no discernible bronchus sign. Univariate analysis identified the bronchus sign (P = .005) and nodule size (P = .04) as statistically significant variables conditioning yield, but on multivariate analysis, only the bronchus sign remained significant (OR, 7.6; 95% CI, 1.8-31.7). No procedure-related complications were observed.

ENB diagnostic yield is highly dependent on the presence of a bronchus sign on CT imaging.

磁导航活检的成功率与病灶是否与支气管相通相关

Electromagnetic Navigation Bronchoscopy: Where Are We Now? Five Years of a Single-Center Experience 

Patrucco, F., Gavelli, F., Daverio, M. et al. Lung (2018) 196: 721. https://doi.org/10.1007/s00408-018-0161-3

Introduction
Electromagnetic navigation (ENB) is a guidance tool used in the diagnosis of solitary pulmonary nodules (SPNs) and masses. Its diagnostic yield is highly variable (38–71%) and a recent study has put in doubt the role of ENB in sampling SPNs in a real-life setting. The aim of this study is to describe the 5-year experience of our center with ENB, analyzing the population, possible confounding factors, and the diagnostic yield and accuracy of this technique.
Methods
We conducted a retrospective observational study including all consecutive patients who underwent ENB for SPNs and masses from January 2011 to December 2015.
Results
We included 113 patients; 79% had SPNs, 21% masses. The majority were localized in the upper and middle lobes (80%) and 61% presented a bronchus sign. 54% of the patients had a previous negative fluoroscopy-guided bronchoscopy. ENB achieved the diagnosis in 78 patients (69%) with 64 malignant and 14 were benign lesions. The diagnostic yield and accuracy of ENB were respectively 0.69 and 0.76. The only factor influencing the ability to reach a diagnosis was the presence of bronchus sign (p = 0.002). No procedural complications were reported.
Conclusion
ENB is a safe procedure with a similar diagnostic yield in the real-life and research setting. Bronchus sign is an important factor in determining the diagnostic yield. ENB efficacy can be maximized by expertise and by a careful selection of each case.