Two-Phase Catheter Path Planning with Curvature Constraints in Endovascular Procedures

Overview

This study presents a two-phase path planning method for steerable catheters in endovascular interventions, addressing curvature limitations and computational efficiency. The approach combines global cubic B-spline curve generation along vascular centerlines with local optimization to satisfy catheter bending constraints, enabling faster and feasible path planning.

Background

Percutaneous coronary intervention (PCI) requires precise catheter navigation through complex vascular anatomies to treat stenotic or occluded vessels. Steerable catheters have limited bending radii, typically ranging from 8.13mm to 171mm, which can restrict their ability to follow vascular centerlines, especially near bifurcations with sharp curvature. Existing path planning methods either strictly follow centerlines or use sampling-based algorithms, but often fail to guarantee feasible paths within catheter curvature limits or require high computational times unsuitable for intraoperative replanning. Real-time path planning is critical due to vascular displacements during procedures and the need for frequent path updates based on sensing feedback.

Data Highlights

The minimum bending radius of steerable catheters reported in literature ranges from 8.13 mm to 171 mm. The catheter bending capability example cited is 13.1 mm. Vascular displacements during catheterization include median cranio-caudal dislocation of 6.7 mm (range 2.1 to 12.3 mm). Existing ant colony optimization methods have average computation times of 12.3 seconds (range 2 to 30 seconds). Tracking and control system frequencies relevant to replanning include 40 Hz for electromagnetic tracking, 1.25 Hz for intra-operative model reconstruction, and 10 Hz for controller frequency.

Key Findings

• The proposed two-phase method first generates a global cubic B-spline curve along vascular centerlines, then locally optimizes segments to meet catheter curvature constraints.
• Centerline extraction uses Voronoi-based minimal action paths maximizing distance from vessel boundaries, providing input points and radii for planning.
• Strictly following centerlines can produce infeasible paths due to curvature exceeding catheter bending limits, especially at bifurcations.
• Sampling-based planners like RRT and adaptive fractal tree methods have variable success rates and often high computational costs unsuitable for real-time use.
• The two-phase approach reduces computational time, facilitating intraoperative path replanning to adapt to vascular deformation and sensing uncertainties.

Clinical Implications

This two-phase path planning framework enables generation of catheter trajectories that respect mechanical bending constraints, improving procedural safety and success. Faster computation supports intraoperative replanning, accommodating vascular motion and enhancing navigation accuracy. Incorporating curvature-aware planning may reduce catheter navigation failures and operator skill dependency during PCI and other endovascular interventions.

Conclusion

The two-phase search method effectively balances adherence to vascular centerlines with catheter curvature limitations, providing feasible and computationally efficient path planning for steerable catheters. This advancement supports real-time intraoperative navigation and has potential to improve outcomes in endovascular procedures.

References

1. Author/Source/Year -- Two-Phase Search Method for Catheter Path Planning in Endovascular Procedures with Curvature Limitations