title: System architecture for a magnetically guided endovascular microcatheter.
abstract: Magnetic resonance imaging (MRI) guided minimally invasive interventions are an emerging technology. We developed a microcatheter that utilizes micro-electromagnets manufactured on the distal tip, in combination with the magnetic field of a MRI scanner, to perform microcatheter steering during endovascular surgery. The aim of this study was to evaluate a user control system for operating, steering and monitoring this magnetically guided microcatheter. The magnetically-assisted remote control (MARC) microcatheter was magnetically steered within a phantom in the bore of a 1.5 T MRI scanner. Controls mounted in an interventional MRI suite, along with a graphical user interface at the MRI console, were developed with communication enabled via MRI compatible hardware modules. Microcatheter tip deflection measurements were performed by evaluating MRI steady-state free precession (SSFP) images and compared to models derived from magnetic moment interactions and composite beam mechanics. The magnitude and direction of microcatheter deflections were controlled with user hand, foot, and software controls. Data from two different techniques for measuring the microcatheter tip location within a 1.5 T MRI scanner showed correlation of magnetic deflections to our model (R(2): 0.88) with a region of linear response (R(2): 0.98). Image processing tools were successful in autolocating the in vivo microcatheter tip within MRI SSFP images. Our system showed good correlation to response curves and introduced low amounts of MRI noise artifact. The center of the artifact created by the energized microcatheter solenoid was a reliable marker for determining the degree of microcatheter deflection and auto-locating the in vivo microcatheter tip.
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, 1001 Potrero Avenue, Room 1X57, San Francisco, CA, 94110, USA.
authors.forename: Ryan S
authors.initials: RS
authors.lastname: Sincic
authors.forename: Curtis J
authors.initials: CJ
authors.lastname: Caton
authors.forename: Prasheel
authors.initials: P
authors.lastname: Lillaney
authors.forename: Scott
authors.initials: S
authors.lastname: Goodfriend
authors.forename: Jason
authors.initials: J
authors.lastname: Ni
authors.forename: Alastair J
authors.initials: AJ
authors.lastname: Martin
authors.forename: Aaron D
authors.initials: AD
authors.lastname: Losey
authors.forename: Neel
authors.initials: N
authors.lastname: Shah
authors.forename: Erin J
authors.initials: EJ
authors.lastname: Yee
authors.forename: Lee
authors.initials: L
authors.lastname: Evans
authors.forename: Vincent
authors.initials: V
authors.lastname: Malba
authors.forename: Anthony F
authors.initials: AF
authors.lastname: Bernhardt
authors.forename: Fabio
authors.initials: F
authors.lastname: Settecase
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Cooke
authors.forename: Maythem
authors.initials: M
authors.lastname: Saeed
authors.forename: Mark W
authors.initials: MW
authors.lastname: Wilson
authors.forename: Steven W
authors.initials: SW
authors.lastname: Hetts
mesh_terms: D000818:Animals; D016477:Artifacts; D057785:Catheters; D057510:Endovascular Procedures / Q000379:methods*; D004867:Equipment Design; D007091:Image Processing, Computer-Assisted; D060526:Magnetic Fields; D053783:Magnetic Resonance Imaging, Interventional; D008280:Magnetics / Q000295:instrumentation*; D023421:Models, Animal; D008962:Models, Theoretical; D019047:Phantoms, Imaging; D013552:Swine