Bayesian Optimization for Design of Multi-Actuator Soft Catheter Robots

Development of decision support tools by model order reduction for active endovascular navigation

Endovascular therapies enable minimally invasive treatment of vascular pathologies by guiding long tools towards the target area. However, certain pathways, such as the Supra-Aortic Trunks (SATs), present complex trajectories that make navigation challenging. To improve catheterization access to these challenging targets, an active guidewire composed of Shape Memory Alloy has been developed. Our study focuses on navigating this device and associated catheters to reach neurovascular targets via the left carotid artery. In previous work, a finite element model was used to simulate the navigation of the active guidewire and catheters from the aortic arch to the branching of the left carotid artery in patient-specific aortas. However, these numerical simulations are computationally intensive, limiting their feasibility for real-time navigation assistance. To address this, we present the development of numerical charts that enable real-time computation based on high-fidelity FE simulations. These charts predict: (1) the behavior of the active guidewire, and (2) the navigation of the guidewire and catheters within specific anatomical configurations, based on guidewire and navigation parameters. Using the High Order Proper Generalized Decomposition (HOPGD) method, these charts achieve accurate real-time predictions with errors below 5 % and a response time of 10-3 seconds, based on a limited number of preliminary high-fidelity computations. These findings could significantly contribute to the development of clinically applicable methods to enhance endovascular procedures and the advance the broader field of neurovascular interventions.

One-Piece 3D-Printed Pneumatic Catheter: Dual-Segment Design with Integrated Robotics Control for Endovascular Interventions

Soft robotics have propelled advancements in medical applications such as endovascular interventions through the development of soft steerable catheters. Despite their potential, existing catheters often require intricate manufacturing or complex control systems due to their inherent hysteresis and nonlinear material properties. This study introduces a novel catheter system featuring a 3D-printed hollow tip with two pneumatic bending units, facilitating rotation about two distinct axes without the need for additional fabrication steps. Finite element analysis simulations were used to optimize the catheter design while minimizing its diameter to 6.4 mm. Furthermore, an external robotic control system was integrated to perform physical experiments to assess the bending capabilities of the catheter tip. After calibration, the system exhibited proficient shape control, achieving a wide bending range from -47° to 169° under the integrated control system, and effectively conforming to 'C', 'S', and 'J' configurations with 0.53 degrees closed-loop accuracy. The catheter prototype demonstrated low hysteresis and high repeatability. The entire catheter system presents a pragmatic and cost-effective approach for the rapid prototyping and development of pneumatic steerable catheters. This novel system is ideally suited for testing preliminary concepts and educational applications in endovascular interventions.

Heat-Mitigated Design and Lorentz Force-Based Steering of an MRI-Driven Microcatheter toward Minimally Invasive Surgery

Catheters integrated with microcoils for electromagnetic steering under the high, uniform magnetic field within magnetic resonance (MR) scanners (3-7 Tesla) have enabled an alternative approach for active catheter operations. Achieving larger ranges of tip motion for Lorentz force-based steering have previously been dependent on using high power coupled with active cooling, bulkier catheter designs, or introducing additional microcoil sets along the catheter. This work proposes an alternative approach using a heat-mitigated design and actuation strategy for a magnetic resonance imaging (MRI)-driven microcatheter. A quad-configuration microcoil (QCM) design is introduced, allowing miniaturization of existing MRI-driven, Lorentz force-based catheters down to 1-mm diameters with minimal power consumption (0.44 W). Heating concerns are experimentally validated using noninvasive MRI thermometry. The Cosserat model is implemented within an MR scanner and results demonstrate a desired tip range up to 110° with 4° error. The QCM is used to validate the proposed model and power-optimized steering algorithm using an MRI-compatible neurovascular phantom and ex vivo kidney tissue. The power-optimized tip orientation controller conserves as much as 25% power regardless of the catheter's initial orientation. These results demonstrate the implementation of an MRI-driven, electromagnetic catheter steering platform for minimally invasive surgical applications without the need for camera feedback or manual advancement via guidewires. The incorporation of such system in clinics using the proposed design and actuation strategy can further improve the safety and reliability of future MRI-driven active catheter operations.

Physics-Informed Modeling and Control of Multi-Actuator Soft Catheter Robots

Catheter-based endovascular interventional procedures have become increasingly popular in recent years as they are less invasive and patients spend less time in the hospital with less recovery time and less pain. These advantages have led to a significant growth in the number of procedures that are performed annually. However, it is still challenging to position a catheter in a target vessel branch within the highly complicated and delicate vascular structure. In fact, vessel tortuosity and angulation, which cause difficulties in catheterization and reaching the target site, have been reported as the main causes of failure in endovascular procedures. Maneuverability of a catheter for intravascular navigation is a key to reaching the target area; ability of a catheter to move within the target vessel during trajectory tracking thus affects to a great extent the length and success of the procedure. To address this issue, this paper models soft catheter robots with multiple actuators and provides a time-dependent model for characterizing the dynamics of multi-actuator soft catheter robots. Built on this model, an efficient and scalable optimization-based framework is developed for guiding the catheter to pass through arteries and reach the target where an aneurysm is located. The proposed framework models the deflection of the multi-actuator soft catheter robot and develops a control strategy for movement of catheter along a desired trajectory. This provides a simulation-based framework for selection of catheters prior to endovascular catheterization procedures, assuring that given a fixed design, the catheter is able to reach the target location. The results demonstrate the benefits that can be achieved by design and control of catheters with multiple number of actuators for navigation into small vessels.