Cone-Beam CT With Augmented Fluoroscopy Combined With Electromagnetic Navigation Bronchoscopy for Biopsy of Pulmonary Nodules

Abstract

Background: Electromagnetic navigation bronchoscopy (ENB) has been widely adopted as a guidance technique for biopsy of peripheral lung nodules. However, ENB is limited by the lack of real-time confirmation of the biopsy devices. Intraprocedural cone-beam computed tomography (CBCT) imaging can be utilized to assess or confirm the location of biopsy devices. The aim of this study is to determine the safety and diagnostic yield (DY) of image fusion of intraprocedural CBCT data with live fluoroscopy (augmented fluoroscopy) during ENB-guided biopsy of peripheral lung nodules.

Methods: Data from 75 consecutive patients who underwent biopsy with ENB was collected retrospectively. Patients underwent CBCT imaging while temporarily suspending mechanical ventilation. CBCT data were acquired and 3-dimensional segmentation of nodules was performed using commercially available software (OncoSuite). During ENB, the segmented lesions were projected and fused with live fluoroscopy enabling real-time 3-dimensional guidance.

Results: A total of 93 lesions with a median size of 16.0 mm were biopsied in 75 consecutive patients. The overall DY by lesion was 83.7% (95% confidence interval, 74.8%-89.9%). Multivariate regression analysis showed no independent correlation between lesion size, lesion location, lesion visibility under standard fluoroscopy, and the presence of a bronchus sign with DY. Pneumothorax occurred in 3 patients (4%).

Conclusion: Intraprocedural CBCT imaging with augmented fluoroscopy is feasible and effective and is associated with high DY during ENB-guided biopsies.

FIGURE 1

Illustration of the different imaging sources involved using CBCT with AF during ENB-guided biopsy procedures. CT data were acquired before the procedure (Yellow arrow shows the target nodule) (A). Intraoperative CBCT data were acquired and 3-dimensional nodule segmentation was performed (B). Three-dimensional nodule segmentation was visualized in overlay with live fluoroscopy: AF (C). AF indicates augmented fluoroscopy; CBCT, cone-beam computed tomography; ENB, electromagnetic navigation bronchoscopy.

FIGURE 2

Comparison of standard fluoroscopy (A) and augmented fluoroscopy (B) for a fluoroscopically invisible nodule. The blue volume was segmented from cone-beam computed tomography data and automatically projected using dedicated software (OncoSuite; Philips).

FIGURE 3

The flowchart of the study. Diagnostic yield per lesion was calculated by dividing the malignant lesions (n=63) and the benign lesions (n=14) by the total number of lesions (n=92, excluding one patient lost to follow-up), resulting in a diagnostic yield per lesion of 83.7% (95% CI, 74.8%-89.9%). CI indicates confidence interval; CT, computed tomography; ENB, electromagnetic navigation bronchoscopy; SBRT, stereotactic body radiation therapy.