542 - CT Guidance for Intravascular Procedures at 200x Lower Dose via Pulsed X-ray Sparse Acquisition

Purpose: 2D fluoroscopy remains the clinical standard for intravascular guidance, but its limited spatial resolution and inability to capture 3D anatomy hinder accuracy. Hybrid CT-fluoroscopy systems have been explored, but patient motion, tool artifacts, and radiation concerns limit their utility. We propose a real-time, dose-efficient 3D CT guidance approach using a novel pulsed X-ray tube and a prior-based reconstruction method. We combined ultra-fast pulsed X-ray acquisition with a Reconstruction of Difference (RoD) algorithm. RoD uses a high-quality reference scan to directly reconstruct anatomical or device-related changes from sparse follow-up scans, allowing for high temporal resolution at ultra-low dose. This is particularly suited for detecting contrast changes and tracking interventional tools. Traditional X-ray tubes are constrained by thermionic emission delays. The Quantix160™ gridded cathode tube (GE HealthCare) enables microsecond-level beam control, operating ~2000× faster than analog CT tubes. This allows for sparse-view acquisition with precise timing, ideal for dynamic guidance.

Materials and Methods: A 3D-printed abdominal aorta model was placed in a human pelvis phantom. A 3Fr microcatheter and 0.018" guidewire were positioned using a robotic steering system. Axial CT scans (16 cm coverage) were acquired with full (1284) and sparse projections (24, 12, 6), simulating 50x, 100x, and 200x dose reductions. Images were reconstructed using filtered back projection (FBP) and RoD. A no-guidewire scan served as the reference for RoD.

Results: FBP reconstructions suffered from artifacts under sparse sampling. In contrast, RoD consistently visualized the guidewire and catheter in 3D, even at 200x dose reduction.

Conclusion: Pulsed X-ray CT combined with RoD reconstruction enables substantial radiation dose reduction while preserving device visibility. This approach supports accurate 3D guidance for endovascular interventions, potentially replacing 2D fluoroscopy in select applications. This method provides a path toward real-time, low-dose 3D CT guidance for vascular procedures, improving localization accuracy while drastically reducing radiation exposure to both patients and providers.