Continuous-sweep limited angle (CLA) fluoroscopy acquires x-ray images during continuous back-and-forth rotation of the C-arm allowing time-resolved 3D reconstruction of curvilinear devices. This method was previously investigated for the navigation of catheters through the airways. The purpose of this work was to extend and evaluate CLA for the guidance of percutaneous needles in the lung. In a porcine study, needles were inserted along anteroposterior, medio-lateral, and cranial-caudal trajectories during CLA imaging. The needle was segmented in the 2D projection images using a deeplearning- based segmentation approach and the corresponding 3D trajectory was reconstructed using an iterative modelbased approach to minimize the distance between a spline model and the 2D segmentations. Needle segmentation accuracies in 2D images were between 99.3 and 99.6%. The 3D reconstruction accuracies were evaluated using projection images corresponding to CLA acquisitions from CBCT scans, where the conventional CBCT reconstruction was used as reference. The highest 3D reconstruction accuracies were observed for needle trajectories parallel to the gantry rotation axis with a median [25th and 75th percentile] root mean squared distance of 0.8 mm [0.6; 1.2] and a tip localization error of 1.7 mm [0.8; 3.0] using an angular range of 10° for device reconstruction. While care must be taken to ensure that the primary extent of the device is in the direction of the C-arm axis of rotation, CLA imaging guidance would address some of the challenges experienced with conventional CT guidance such as patient access, larger coverage in CC direction, and real-time imaging feedback.
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