04:03 PM Abstract No. 293 Cone-beam CT with augmented fluoroscopy: a novel approach for navigating airways and guiding transbronchial interventions

Transbronchial microwave (MW) ablation is a recently developed bronchoscopic therapy for small pulmonary malignancies. X-ray based guidance techniques would allow interventional radiologists to perform the procedure. The purpose of this study was to assess the feasibility and target accuracy of using cone-beam CT (CBCT) with augmented fluoroscopy to navigate airways. A 5Fr angled catheter and angled glidewire were used to navigate to 16 peripheral targets in the lungs of two ∼ 50kg female swine. General anesthesia was used and endotracheal access was via an 8Fr sheath placed through a Bodai adapter. Navigations were performed during free breathing (n=9) and breath holds (n=7). The pathway from the carina to the target as well as intervening non-target branches were manually drawn on a baseline CBCT. Navigation was then performed with the pathway overlaid on live fluoroscopy. Target accuracy (distance from catheter/wire to target) was confirmed on CBCT. Logistic regression was performed to determine if the number of targeting attempts was impacted by target-to-carina distance, target-to-pleura distance, target bronchus diameter, respiratory motion, or number of intervening bronchial branch points. Fluoroscopy times were recorded. There were no complications. The target was reached in 100% (16/16) of cases: 11 (68.8%) after 1 attempt, 4 (25%) after 2 attempts, and 1 (6.2%) after 3 attempts. Median (range) target accuracy, carina-to-target distance, target-to-pleura distance and target bronchus diameter were 3.8mm (0-11.8mm), 10.3cm (7.1-12.4cm), 1.5cm (1.1-2.6cm), and 2.2mm (1.4-3.1mm), respectively. There was a median of 8 branch points (range: 4-14) between the carina and target. Median fluoroscopy time to reach a target was 45.5s (range: 13.7-220.9s). There was no relationship between achieving the target after 1 attempt and carina-to-target distance, target-to-pleura distance, number of bronchial branch points, respiratory motion, or target bronchi diameter. CBCT with augmented fluoroscopy is a feasible and accurate method for endobronchial navigation that may enable transbronchial interventions, including ablation, using only x-ray guidance.