Performance of interventions with manipulator-driven real-time MR guidance: implementation and initial in vitro tests

Area of Science:

• Medical Imaging
• Robotics
• Minimally Invasive Surgery

Background:

• Magnetic Resonance Imaging (MRI) offers excellent soft-tissue contrast for surgical guidance.
• MR-compatible robotic systems are crucial for enabling interventions within the MRI scanner environment.
• Real-time MR guidance enhances the precision and safety of interventional procedures.

Purpose of the Study:

• To implement and evaluate an MR-compatible manipulator system for real-time MRI-guided interventions.
• To assess the performance of manipulator-driven dynamic MR imaging for tracking and guidance.
• To validate the system's accuracy in target acquisition and path planning within a cylindrical MRI scanner.

Main Methods:

• A seven degree-of-freedom MR-compatible manipulator with man-in-the-loop control (GUI or master/slave).
• Real-time MR guidance using dynamic imaging plane updates synchronized with manipulator motion.
• Phantom studies conducted in a 1.5-T cylindrical MRI scanner using triggered GRE and TrueFISP sequences.

Main Results:

• Accurate target acquisition with 3.2 mm precision and 2.5-degree path orientation accuracy.
• Successful path planning, including obstacle negotiation and needle bending.
• Signal-to-noise ratio (SNR) for TrueFISP was 18.6+/-2.4 during manipulator operation; triggered GRE achieved 61.3+/-1.8.

Conclusions:

• The developed MR-compatible manipulator system enables manually directed interventions within cylindrical MRI scanners.
• Real-time MR guidance is feasible and effective for tracking and visualizing interventional tool motion.
• The system demonstrates potential for enhancing precision and safety in MR-guided procedures.