Remote control catheter navigation: options for guidance under MRI.
BACKGROUND
Image-guided endovascular interventions have gained increasing popularity in clinical practice, and magnetic resonance imaging (MRI) is emerging as an attractive alternative to X-ray fluoroscopy for guiding such interventions. Steering catheters by remote control under MRI guidance offers unique challenges and opportunities.


METHODS
In this review, the benefits and limitations of MRI-guided remote control intervention are addressed, and the tools for guiding such interventions in the magnetic environment are summarized. Designs for remote control catheter guidance include a catheter tip electromagnetic microcoil design, a ferromagnetic sphere-tipped catheter design, smart material-actuated catheters, and hydraulically actuated catheters. Remote control catheter guidance systems were compared and contrasted with respect to visualization, safety, and performance. Performance is characterized by bending angles achievable by the catheter, time to achieve bending, degree of rotation achievable, and miniaturization capacity of the design. Necessary improvements for furthering catheter design, especially for use in the MRI environment, are addressed, as are hurdles that must be overcome in order to make MRI guided endovascular procedures more accessible for regular use in clinical practice.


CONCLUSIONS
MR-guided endovascular interventions under remote control steering are in their infancy due to issues regarding safety and reliability. Additional experimental studies are needed prior to their use in humans.
Department of Radiology and Biomedical Imaging, University of California San Francisco, 505 Parnassus Avenue, L-352, San Francisco, CA 94143-0628, USA. steven.hetts@ucsf.edu
Leah
L
Muller
Maythem
M
Saeed
Mark W
MW
Wilson
Steven W
SW
Hetts
D057785:Catheters / Q000009:adverse effects; D057510:Endovascular Procedures / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design; D006801:Humans; D053783:Magnetic Resonance Imaging, Interventional / Q000009:adverse effects; D008904:Miniaturization; D012371:Robotics; D013813:Therapy, Computer-Assisted / Q000295:instrumentation* / Q000379:methods*