Method for 3D navigation of airways on a single C-arm using multi-sweep limited angle acquisition and frame-by-frame device reconstruction

Abstract

Accurate and efficient 3D catheter navigation within the airways is crucial for transbronchial procedures, including biopsy and tumor ablation. While electromagnetic tracking for 3D tip localization exists, it requires specialized equipment, timeconsuming registration steps and is prone to CT-to-body divergence. Recently developed techniques allow 3D reconstruction of catheters and curvilinear devices from two simultaneously acquired projection images, but they require a biplane C-arm x-ray system which is not widely available in clinical practice. This study investigates a method of timeresolved 3D tracking of catheters using the more widely available single-plane C-arm system. Imaging was performed using an acquisition protocol where the C-arm continuously rotates back and forth within a limited angular range while acquiring x-ray images. The catheter reconstruction was performed using a sliding window of the most recent x-ray images, which captures information on device shape and position versus time. A model-based approach was used to estimate the catheter shape and position at the time of the last x-ray image acquisition. To evaluate the approach, a pig study was performed where the proposed reconstruction was compared to a gold standard extracted from cone-beam CT (CBCT). The average 3D root mean squared distance between single plane and CBCT reconstruction was 0.8 ± 0.3mm for a stationary catheter and 2.4 ± 1.4mm for a catheter moving at ~1 cm/s. The tip localization error ranged from 1.0 ± 0.4mm to 3.8 ± 2.2mm. The results indicate catheter navigation based on the proposed single plane C-arm imaging technique is feasible with reconstruction errors on the order of the typical ablation catheter diameter (2.0 - 3.2mm).