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

Abstract

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.

Design and Development of a Lorentz Force-Based MRI-Driven Neuroendoscope

“…This paper uses the inverse kinematics of the Cosserat model to predict the tip bending angles of the proposed endoscope design as detailed in [21]. Similarly, the endoscope is modeled as a cantilever beam undergoing an external torque and tip force.…”

“…A value of 0.33 was determined (Figure 4) but to ease manufacturing, a ratio of 0.5 was used in this study with additional parameters found in Table I. Microcoil bundles were manufactured starting with the axial coil forming the outer core of the endoscope cap, following the same fabrication process as previously described [21]. The resulting coil bundle was attached to the endoscope cap as shown in Figure 3.…”

“…Moreover, the image distortion can be controlled since the image artifacts only occur when coils are activated. In our previous work, we demonstrated a new approach to mitigate Lorentz force-based heating effects using the inverse kinematics of the device to steer within confined workspaces [21]. This paper proposes the design and actuation of an MRI-driven endoscope for intraventricular navigation and tumor ablation.…”

Collective Behaviors of Magnetic Microparticle Swarms: From Dexterous Tentacles to Reconfigurable Carpets

“…In the past few years, the development of mobile microrobots has been boosted with advances in material science, , biotechnology, etc . Intriguing achievements have emerged in various applications at the cellular or molecular level, − where a single microrobot has exhibited mature abilities in executing navigation, − delivery, , actuation, − and manipulation tasks. , From the perspective of microrobotics, real-time interactive communication is almost inaccessible among present simple-structure magnetic microrobots because there are no onboard computational abilities and integrated sensors to process the necessary information. This is a vital barrier to overcome for efficiently organizing microrobots.…”

Self-vectoring electromagnetic soft robots with high operational dimensionality

“…More importantly, the reported reprogramming methods to modify the polarization of magnetic domains in soft materials based on heating, are slow, tedious and impossible for insitu customization [22][23][24] . To solve these issues, electromagnetic actuators have lately been noticed as a promising alternative by replacing magnetic domains in soft materials with conductors passing electric currents, which can be easily controlled to generate a desired Lorentz force in response to a constant external magnetic field [25][26][27] . Such actuators show advantages of fast reprogrammable control, domain selective actuation, and MRI-compatibility upon soft magnetic systems.…”