Virtual fluoroscopy during transbronchial biopsy for locating ground-glass nodules not visible on X-ray fluoroscopy

Abstract

Background: Virtual fluoroscopy (VF) is a novel guided technique that provides ray summation images of target lesions similar to X-ray fluoroscopy. Endobronchial ultrasound with a guide sheath (EBUS-GS) is a useful modality for imaging ground-glass nodules (GGNs) but is not ideal for GGNs that cannot be detected on X-ray fluoroscopy. We evaluated whether the addition of VF to EBUS-GS improved the diagnostic yield. Methods: Consecutive patients who had undergone diagnostic bronchoscopy for GGNs that were not detected on X-ray fluoroscopy between September 2012 and January 2016 were retrospectively enrolled. The patients were divided into two groups: a non-VF group [performed using conventional thin-section computed tomography (CT), X-ray fluoroscopy, EBUS-GS, and virtual bronchoscopy for reference], and a VF group (performed using additional VF to non-VF group). We then compared the diagnostic yields between the two groups and performed a multivariate analysis to identify factors associated with an increased diagnostic yield. Results: A total of 74 patients (VF, 35 patients; non-VF, 39 patients) were enrolled and were included in the analysis. The diagnostic yield was significantly higher in the VF group (77.1%) than in the non-VF group (51.2%, P=0.030). There were no clinically significant complications in either group. In the multivariate analysis, a positive bronchus sign [odds ratio (ORs), 5.41; 95% confidence interval (CI), 1.36-21.40] and the use of VF (odds ratio, 3.68; 95% confidence interval, 1.16-11.60) were significantly associated with successful bronchoscopic diagnosis. Conclusions: The addition of VF to EBUS-GS helped to identify GGNs that were not visible on X-ray fluoroscopy.