Size and vision: Impact of fluoroscopic navigation, digital tomosynthesis, and continuous catheter tip tracking on diagnostic yield of small, bronchus sign negative lung nodules.

Introduction: Accurate biopsies of lung nodules, including small (<2 cm), bronchus sign negative lesions, remain challenging. Technological advances, however, may improve outcomes. We describe our experience using a novel system combining fluoroscopic navigation with digital tomosynthesis and continuous catheter tip tracking to guide lung nodule biopsies.

Methods: Demographic data, procedural characteristics, and biopsy results from prospectively enrolled patients were collected.

Results: 159 nodules (144 patients) were biopsied. Average nodule size was 22.2 ± 15.2 mm (axial), 21.7 ± 13.9 mm (coronal), and 33.2 ± 20.5 mm (sagittal), with 45% (n = 72) <2 cm in all dimensions and 66% (n = 105) without a bronchus sign. Diagnostic yield was 84% (134/159), with malignancy (n = 75, 47%) most common. A diagnosis was obtained in 75% (n = 54/72) of lesions that were <2 cm in all dimensions and 79% (n = 83/105) of bronchus sign negative lesions. Unadjusted generalized mixed-effects logistic regression models showed that nodule size as a categorical variable (>2 cm in any dimension) and as a continuous variable in the coronal dimension, the presence of a bronchus sign, and a concentric radial EBUS view had an increased odds ratio for diagnosis. A concentric radial EBUS view also had an increased OR for diagnosis in a fully adjusted mixed-effects logistic regression model.

Conclusion: Fluoroscopic navigation with digital tomosynthesis and continuous catheter tip tracking shows an overall improved diagnostic accuracy compared to historical controls, including for small, bronchus sign negative lesions. Future studies clarifying the optimal modality for patients with different nodules will be of importance to provide the most appropriate procedure tailored to each individual lesion's unique characteristics.