Intra-op Image-guided Robotics

Shape Tracking and Feedback Control of Cardiac Catheter Using MRI-guided Robotic Platform

Cardiac electrophysiology is an effective treatment for atrial fibrillation, in which a long, steerable catheter is inserted into the heart chamber to conduct radio frequency ablation. Magnetic resonance imaging (MRI) can provide enhanced intraoperative monitoring of the ablation progress as well as the localization of catheter position. However, accurate and real-time tracking of the catheter shape and its efficient manipulation under MRI remains challenging. In this work, we designed a shape tracking system that integrates a multicore fiber Bragg grating (FBG) fiber and tracking coils with a standard cardiac catheter. Both the shape and positional tracking of the bendable section could be achieved. A learning-based modeling method is developed for cardiac catheters, which uses FBG-reconstructed three-dimensional curvatures for model initialization. The proposed modeling method was implemented on an MRI-guided robotic platform to achieve feedback control of a cardiac catheter. The shape tracking performance was experimentally verified, demonstrating 2.33° average error for each sensing segment and 1.53 mm positional accuracy at the catheter tip. The feedback control performance was tested by autonomous targeting and path following (average deviation of 0.62 mm) tasks. The overall performance of the integrated robotic system was validated by a pulmonary vein isolation simulator with ex-vivo tissue ablation, which employed a left atrial phantom with pulsatile liquid flow. Catheter tracking and feedback control tests were conducted in an MRI scanner, demonstrating the capability of the proposed system under MRI.

[Video: Shape Tracking and Feedback Control of Cardiac Catheter Using MRI-guided Robotic Platform

Soft Robotic Manipulator for Intra-operative MRI-guided Transoral Laser Microsurgery

Magnetic resonance (MR) imaging (MRI) provides compelling features for the guidance of interventional procedures, including high-contrast soft tissue imaging, detailed visualization of physiological changes, and thermometry. Laser-based tumor ablation stands to benefit greatly from MRI guidance because 3D resection margins alongside thermal distributions can be evaluated in real time to protect critical structures while ensuring adequate resection margins. However, few studies have investigated the use of projection-based lasers like those for transoral laser microsurgery, potentially because dexterous laser steering is required at the ablation site, raising substantial challenges in the confined MRI bore and its strong magnetic field. Here, we propose an MR-safe soft robotic system for MRI-guided transoral laser microsurgery. Owing to its miniature size (Ø12 × 100 mm), inherent compliance, and five degrees of freedom, the soft robot ensures zero electromagnetic interference with MRI and enables safe and dexterous operation within the confined oral and pharyngeal cavities. The laser manipulator is rapidly fabricated with hybrid soft and hard structures and is powered by microvolume (<0.004 milliter) fluid flow to enable laser steering with enhanced stiffness and lowered hysteresis. A learning-based controller accommodates the inherent nonlinear robot actuation, which was validated with laser path–following tests. Submillimeter laser steering accuracy was demonstrated with a mean error < 0.20 mm. MRI compatibility testing demonstrated zero observable image artifacts during robot operation. Ex vivo tissue ablation and a cadaveric head-and-neck trial were carried out under MRI, where we employed MR thermometry to monitor the tissue ablation margin and thermal diffusion intraoperatively

[Video: Soft robotic manipulator for intraoperative MRI-guided transoral laser microsurgery

A Robotic Platform to Navigate MRI-guided Focused Ultrasound System

Focused ultrasound (FUS) technology attracts increasing interests accrediting to its non-invasive and painless treatment of tumors. Magnetic resonance imaging (MRI) guidance has been introduced to monitor this procedure, thus allowing the ultrasound foci to be precisely controlled. However, manual positioning of the FUS transducers is challenging, especially for the intra-operative (intra-op) adjustment in the MRI room. Currently, there are very few devices capable to provide robotic transducer positioning for the treatment of abdominopelvic organ diseases under MRI. The high intensity focused ultrasound (HIFU) spot would have to be “steered” to ablate large (>Ø 3.5 cm) or multiple tumors (e.g., in liver). To this end, we proposed a hydraulic-driven tele-operated robot platform that enables 5-DoF manipulation of the FUS transducer. Even operated close to the MRI iso-center, the robot can guarantee zero electromagnetic (EM) artifact to the MR image. Our proof-of-concept robot prototype can offer a large workspace (100 mm × 100 mm × 35 mm) for FUS foci steering. Accurate manipulation (0.2 mm in translation, 0.4° in rotation) of the FUS transducer holder is achieved using rolling diaphragmsealed hydraulic actuators. The robot control responsiveness (from 0.1 to 4 Hz) is also evaluated to show the potential to compensate for the spot tracking error induced by respiratory motion. We also demonstrate the use of wireless radiofrequency (RF) markers to continuously register the robot task space in the MRI coordinates.

[Video: A Robotic Platform to Navigate MRI-guided Focused Ultrasound System]

Design of a Percutaneous MRI-guided Needle Robot with Soft Fluid-driven Actuator

Percutaneous ablation is a standard therapy for most cases of hepatocellular carcinoma (HCC), which is a general type of primary liver cancer. Magnetic resonance imaging (MRI) offers high-contrast images of soft tissue to monitor the ablation procedure. However, the success of MRI-guided ablation still depends on precise intra-tumor probe placement and skin insertion positioning, both of which require highly experienced operators, and can induce inter-operator variability in ablation results. To solve this, we propose a semi-automated robotic system for MRI-guided percutaneous needle procedures. The compact and lightweight design enables the direct fixture of robot on the patient body and simultaneous needle targeting at multiple locations with several robots. Accurate (0.89 ± 0.31 mm) needle navigation is achieved by incorporating soft fluid-driven actuators with feedback control and stiffness modulation capabilities. The 3D location of the needle guide is reconfirmed by wireless MR tracking coils. With the proposed workflow integrated with the system, the total procedure time is comparable to the MRI-guided radiofrequency ablation for hepatic malignancies.

[Video: Design of a Percutaneous MRI-guided Needle Robot with Soft Fluid-driven Actuator]

High-performance Continuous Hydraulic Motor for MR Safe Robotic Teleoperation

Magnetic resonance imaging (MRI)-guided intervention has drawn increasing attention over the last decade. It is accredited to the capability of monitoring any physiological change of soft tissue with the high-contrast MR images. This also gives rise to the demand for precise tele-manipulation of interventional instruments. However, there is still lack of choices of MR safe actuators that provide high-fidelity robot manipulation. In this project, we present a three-cylinder hydraulic motor using rolling-diaphragm-sealed cylinders, which can provide continuous bidirectional rotation with unlimited range. Both kinematics and dynamics models of the presented motor were studied, which facilitate its overall design optimization and position/torque control. Motor performance, such as step response, frequency response, and accuracy, were experimentally evaluated. We also integrate the motor into our catheter robot prototype designed for intra-operative MRI-guided cardiac electrophysiology (EP), which can provide full-degree-of-freedom and precise manipulation of a standard EP catheter.

[Video: High-performance Continuous Hydraulic Motor for MR Safe Robotic Teleoperation]

MRI-guided Robot for Bilateral Stereotactic Neurosurgery

Stereotactic neurosurgery is a treatment to a variety of movement and neuropsychiatric disorders, such as Parkinson’s disease (PD), essential tremor and major depression. The operation still remains challenging due to its complicated workflow and high demand for surgical accuracy, which can be further complicated by deformation of intracranial contents, namely “brain shift”. These complications create an increasing need for intra-operative MRI-guided stereotaxy. Unlike fluoroscopy/CT, MRI can directly visualize the critical brain structures and targets of interest (e.g., the subthalamic nucleus (STN)). Currently, there are very limited choices of MR safe stereotactic systems. They generally require intensive manual adjustment of the stereotactic frame, and the patient to be transferred in-and-out of the scanner bore. This inevitably disrupts the normal surgical workflow. To this end, we have developed an intra-operative MRI-guided robot for bilateral stereotactic procedures. Its compact design enables robot’s operation within the constrained space of standard imaging head coil. MR-safe and high-performance hydraulic transmissions are incorporated, and wireless MR-based tracking coil units allow real-time positional feedback directly in MR image coordinates.

[Video: ICRA18 Best Conference Paper Award Presentation: Compact Design of a Hydraulic Driving Robot for Intra-operative MRI-guided Bilateral Stereotactic Neurosurgery]

[Video: MRI-guided Robot for Bilateral Stereotactic Neurosurgery]

MRI-guided Robot for Intra-operative Cardiac Catheterization

This robotic catheter platform intends to provide safe and effective electrophysiology (EP) intervention under the guidance of magnetic resonance imaging (MRI). In cardiac EP intervention, a long catheter (>1m) is delivered to the heart chamber where radiofrequency ablation (RFA) is performed to isolate the abnormal electrophysiological signals. The safety and effectiveness of EP intervention can be enhanced by providing high quality intra-operative MR images and MR-conditional robotic platform for effective catheterization. Currently, no existing commercial nor research prototype for robotic catheterization is MR-conditional. We develop the MR-conditional catheter robotic system for effective catheter manipulation that makes use of MR-safe/conditional actuation, intra-operative MRI techniques, real-time visual feedback and an advanced kinematics control method.

[Video: MRI-guided Robot for Intra-operative Cardiac Catheterization]

PUBLICATIONS

[1] G. Fang, M.C.K. Chow, J.D.L. Ho, Z. He, K. Wang, T.C. Ng, J.K.H. Tsoi, P.L. Chan, H.C. Chang, D.T.M. Chan, C. Holsinger, J.Y.K. Chan, K.W Kwok, “Soft Robotic Manipulator for Intra-operative MRI-guided Transoral Laser Microsurgery”, Science Robotics, 6(57), 2021 Detail

[2] Z. Dong, X. Wang, J.D.L. Ho, Z. He, G. Fang, W.L. Tang, X. Xie, C.K. Ching, K.W. Kwok, “Shape Tracking and Feedback Control of Cardiac Catheter Using MRI-guided Robotic Platform – Validation with Pulmonary Vein Isolation Simulator in MRI,” IEEE Transactions on Robotics (TRO) (Early Access), 2022 Detail

[3] J. Dai, Z. He, G. Fang, X. Wang, Y. Li, C.L. Cheung, L. Liang, I.I. Iordachita, H.C. Chang, K.W. Kwok, “A Robotic Platform to Navigate MRI-guided Focused Ultrasound System”, IEEE Robotics and Automation Letters (RA-L), 6(3):5137-5144, 2021 Detail

[4] Z. He, Z. Dong, G. Fang, J.D.L. Ho, C.L. Cheung, H.C. Chang, C.N. Chong, Y.K. Chan, T.M. Chan, K.W. Kwok, “Design of a Percutaneous MRI-guided Needle Robot with Soft Fluid-driven Actuator,” IEEE Robotics and Automation Letters (RA-L), 5(2):2100-2107, 2020. Detail

[5] Z. Dong, Z. Guo, K.H. Lee, G. Fang, W.L. Tang, H.C. Chang, D.T.M. Chan and K.W. Kwok,"High-performance Continuous Hydraulic Motor for MR Safe Robotic Teleoperation," IEEE Robotics and Automation Letters (RA-L) 4(2):1964-1971, 2019 Detail

[6] Z. Guo, Z. Dong, K.H. Lee, C.L. Cheung, H.C. Fu, J.D.L. Ho, H. He, W.S. Poon, D.T.M. Chan, K.W. Kwok,"Compact Design of a Hydraulic Driving Robot for Intra-operative MRI-guided Bilateral Stereotactic Neurosurgery," IEEE Robotics and Automation Letters (RA-L), vol. 3, no. 3, pp. 2515-2522. 2018. Detail

[7] K.H. Lee, D.K.C. Fu, Z. Guo, Z. Dong, M.C.W. Leong, C.L. Cheung, A.P.W. Lee, K.W. Kwok,"MR Safe Robotic Manipulator for MRI-guided Intra-cardiac Catheterization," IEEE/ASME Transactions on Mechatronics (TMech), vol. 23, no. 2, pp. 586-595, 2018. Detail

[8] Z. Guo, T. L. T. Lun, Y. Chen, H. Su, D.T.M. Chan, K.W. Kwok,"Novel Design of an MR-safe Pneumatic Stepper Motor for MRI-guided Robotic Interventions," Proceedings of Hamlyn Symposium on Medical Robotics, 2016, pp. 50-51. Detail

AWARDS

1. Best Conference Paper Award in the IEEE International Conference on Robotics and Automation, 2018 (ICRA’18).
[The best out of 2,539 papers accepted by this top leading conference in robotics]
Authors and title: Z. Guo, Z. Dong, K.H. Lee, C.L. Cheung, H.C. Fu, J.D.L. Ho, H. He, W.S. Poon, D.T.M. Chan, K.W. Kwok, "Compact Design of a Hydraulic Driving Robot for Intra-operative MRI-guided Bilateral Stereotactic Neurosurgery."

2. Finalist for ICRA Best Medical Robotics Paper Award in the IEEE International Conference on Robotics and Automation, 2018 (ICRA’18).
[sponsored by Intuitive Surgical Inc.]
Authors and title: Z. Guo, Z. Dong, K.H. Lee, C.L. Cheung, H.C. Fu, J.D.L. Ho, H. He, W.S. Poon, D.T.M. Chan, K.W. Kwok, "Compact Design of a Hydraulic Driving Robot for Intra-operative MRI-guided Bilateral Stereotactic Neurosurgery."

3. Merit Poster Award in the IEEE International Conference on Robotics and Automation, 2017 (ICRA’17), presented by the workshop C4 Surgical Robots: Compliant, Continuum, Cognitive, and Collaborative.

Authors and title: Z. Dong, Z. Guo, K.C.D. Fu, K.H. Lee, M.C.W. Leong, C.L. Cheung, A.P.W. Lee, W. Luk and K.W. Kwok, "A Robotic Catheter System for MRI-guided Cardiac Electrophysiological Intervention."

4. Best Live Demonstration prize – Surgical Robot Challenge 2016, organized by EPSRC UK-RAS Network.

Title: "MR-conditional Catheter Robot for MRI-guided Cardiac Electrophysiological Intervention."

PATENTS

1. US Provisional Pat: “MRI Tracking Device Design, Fabrication, and Methods of use for MRI-Guided Robotic System”: US 62/640,798 (Filed on 9 Mar, 2018)

2. US Provisional Pat: “Fluid Powered Master-Slave Actuation for MRI-Guided Interventions”: US 62/640,302 (Filed on 8 Mar, 2018)

3. US Provisional Pat: “Robotic Stereotactic System for MRI-Guided Neurosurgery”: US 62/623,280 (Filed on 29 Jan, 2018)

4. PCT Provisional Pat: Robotic Catheter System for MRI-guided Cardiovascular Interventions: PCT/CN2017/089701 (Filed on 2017. Licensed by APTUS Therapeutics Limited.)

5. US Provisional Pat: Robotic Catheter System for MRI-guided Cardiovascular Interventions: 04435/005210-US0 (Filed on Jun 24, 2016. Licensed by APTUS Therapeutics Limited.)