Gradient Pulling of a Tethered Robot via a Magnetic Resonance Imaging System

Magnetically actuated soft robots offer significant advantages for minimally invasive medical procedures by enabling precise control and navigation in confined anatomical environments. This study explores the feasibility of using the gradient fields of a Magnetic Resonance Imaging (MRI) system to actuate a tethered robotic guidewire, demonstrating a novel leader-follower approach for controlled navigation. A spherical low-carbon steel ball, tethered via a medical-grade filament, serves as the actuated magnetic tip, while a flexible silicone sleeve follows the tip trajectory to establish a stable guidewire. By leveraging the MRI’s built-in magnetic gradients, we achieve stepwise actuation and thus pathway formation inside the MRI bore. We analyze the magnetic pulling force, the friction effects of the tether and sleeve combination, and the signal void introduced by the presence of ferrous materials in the MRI bore, optimizing the system to minimize imaging distortion while maintaining effective actuation. Experimental results demonstrate successful free space deformation and gradient-induced forward movement followed by follower navigation through constrained pathways, validating the method’s potential for MRI-guided endovascular interventions.