Magnetic Guidewire Control without Tip-Angle Detection in Sharply Curved Blood Vessel

This paper proposes a position control algorithm for a magnetic guidewire without detection of tip-angle in sharply curved blood vessels. Key element of the proposed tip positioning control is to track a desired path regenerated in a blood vessel by a feeding control and an electromagnetic actuation (EMA) control. The path-regeneration creates an improved path in terms of properties of a magnetic guidewire and the size of a blood vessel when a magnetic guidewire can not traverse an original path. Based on a desired path, the feeding device and the EMA system make the translational and the rotational motion of a magnet tip, respectively. In this paper, for the EMA system, one pair of Helmholtz coil is employed to steer the magnet tip by adjusting the direction of the magnetic field. For the positioning control, a magnet tip is controlled with a regenerated path in order to follow a desired path without information of tip orientation. The proposed control methodology was verified through experiments on a phantom of sharply curved blood vessels. The experimental results proved that the proposed method could overcome the sharply curved blood vessel by control of the tip position of the guidewire with high accuracy in real-time.