Background: Shape-sensing robotic-assisted bronchoscopy (ssRAB) enables sampling smaller and more peripheral pulmonary nodules. Diagnostic yield for nodules less than 1cm and 1 to 2 cm has been reported as 66.6% and 70.4%, respectively. Three-dimensional fluoroscopy (3D-F) allows visualization of the biopsy tool in relation to the target nodule in three planes, potentially improving diagnostic accuracy for nodules less than 2cm in size.

Aims: Compare ssRAB diagnostic yield for pulmonary nodules less than 2cm pre and post-use of 3D-F.

Methods: Retrospective study of patients who underwent ssRAB for evaluation of pulmonary nodules less than 2cm from September 2021 to January 2023. Primary outcome was comparing diagnostic yield pre- and post-use of 3D-F. Secondary outcomes were subgroup analysis by size, sensitivity for malignancy, and complications requiring intervention.

Results: 119 nodules were biopsied from 114 patients. Median lesion size was 1.32 x 1.1cm (IQR 1.04 ? 1.71; 0.90 ? 1.4). Target nodules were divided in two groups: pre (n = 53) and post (n= 66) 3D-F. Overall diagnostic yield was significantly higher for post-3D-F compared to pre-3D-F (83.3% vs 67.9%; p = 0.024). Subgroup analysis by size reported a diagnostic yield significantly higher for nodules < 1cm post-3D-F (84.6% vs 50%; p = 0.036). For nodules 1-2cm, diagnostic yield was 72.1% for pre-3D-F and 82.7% for post-3D-F. Overall sensitivity for malignancy was 86.7% for pre-3D-F and 88.1% for post-3D-F. Five pneumothoraxes were reported, with one patient requiring chest tube.

Conclusion: The use of 3D-fluoroscopy in ssRAB significantly improves diagnostic yield for lung nodules less than 2cm.