Accuracy of x-ray image-based 3D localization from two C-arm views: a comparison between an ideal system and a real device

Abstract

C-arm X-ray imaging devices are commonly used for minimally invasive cardiovascular or other interventional procedures. Calibrated state-of-the-art systems can, however, not only be used for 2D imaging but also for three-dimensional reconstruction either using tomographic techniques or even stereotactic approaches.To evaluate the accuracy of X-ray object localization from two views, a simulation study assuming an ideal imaging geometry was carried out first. This was backed up with a phantom experiment involving a real C-arm angiography system. Both studies were based on a phantom comprising five point objects. These point objects were projected onto a flat-panel detector under different C-arm view positions. The resulting 2D positions were perturbed by adding Gaussian noise to simulate 2D point localization errors. In the next step, 3D point positions were triangulated from two views. A 3D error was computed by taking differences between the reconstructed 3D positions using the perturbed 2D positions and the initial 3D positions of the five points. This experiment was repeated for various C-arm angulations involving angular differences ranging from 15 o to 165 o . The smallest 3D reconstruction error was achieved, as expected, by views that were 90 o degrees apart. In this case, the simulation study yielded a 3D error of 0.82 mm ± 0.24 mm (mean ± standard deviation) for 2D noise with a standard deviation of 1.232 mm (4 detector pixels). The experimental result for this view configuration obtained on an AXIOM Artis C-arm (Siemens AG, Healthcare Sector, Forchheim, Germany) system was 0.98 mm ± 0.29 mm, respectively.These results show that state-of-the-art C-arm systems can localize instruments with millimeter accuracy, and that they can accomplish this almost as well as an idealized theoretical counterpart. High stereotactic localization accuracy, good patient access, and CT-like 3D imaging capabilities render state-of-the-art C-arm systems ideal devices for X-ray based minimally invasive procedures.

Cryo-balloon reconstruction from two views

“…For the simulation, we computed 250 spheres each at a different positions in 3-D space within a maximum distance to the center of the volume of 150 mm and with a radius between 5 mm and 15 mm. The simulation was performed using ideal C-arm projection matrices as described in [15,16]. The C-arm positions were chosen to be 90 o apart which is similar to a clinical setup.…”

3D model-based catheter tracking for motion compensation in EP procedures

“…In the next step, we applied the motion estimated by catheter tracking to the catheter tip to move it from its 3-D position in the previous frame to the next frame. Finally, we compared the 3-D position reached by applying the estimated motion to the actual 3-D reference point obtained by triangulation [23,24]. In the end, the error was calculated as the Euclidean distance in 3-D space.…”

“…The special case implies that there was one ellipse in one view, while it collapsed to a line in the other view. The projection matrices for the simulation were computed as described in [23,24].…”

Navigation for fluoroscopy-guided cryo-balloon ablation procedures of atrial fibrillation

“…Given the rotation and translation, the central rays r A , r B ∈ R 3 for both cones can be calculated and intersected by the method presented in [15] to find the center of the reconstructed sphere w c ∈ R 3 . To calculate the radius of the reconstructed sphere, each cone is intersected with a 3-D plane parallel to the imaging plane at the position of the calculated center w c .…”