title: Magnetic catheter manipulation in the interventional MR imaging environment.
abstract: OBJECTIVE
  To evaluate deflection capability of a prototype endovascular catheter, which is remotely magnetically steerable, for use in the interventional magnetic resonance (MR) imaging environment.
  
  
  METHODS
  Copper coils were mounted on the tips of commercially available 2.3-3.0-F microcatheters. The coils were fabricated in a novel manner by plasma vapor deposition of a copper layer followed by laser lithography of the layer into coils. Orthogonal helical (ie, solenoid) and saddle-shaped (ie, Helmholtz) coils were mounted on a single catheter tip. Microcatheters were tested in water bath phantoms in a 1.5-T clinical MR scanner, with variable simultaneous currents applied to the coils. Catheter tip deflection was imaged in the axial plane by using a "real-time" steady-state free precession MR imaging sequence. Degree of deflection and catheter tip orientation were measured for each current application.
  
  
  RESULTS
  The catheter tip was clearly visible in the longitudinal and axial planes. Magnetic field artifacts were visible when the orthogonal coils at the catheter tip were energized. Variable amounts of current applied to a single coil demonstrated consistent catheter deflection in all water bath experiments. Changing current polarity reversed the observed direction of deflection, whereas current applied to two different coils resulted in deflection represented by the composite vector of individual coil activations. Microcatheter navigation through the vascular phantom was successful through control of applied current to one or more coils.
  
  
  CONCLUSIONS
  Controlled catheter deflection is possible with laser lithographed multiaxis coil-tipped catheters in the MR imaging environment.
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA 94107, USA.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Wilson
authors.forename: Alastair B
authors.initials: AB
authors.lastname: Martin
authors.forename: Prasheel
authors.initials: P
authors.lastname: Lillaney
authors.forename: Aaron D
authors.initials: AD
authors.lastname: Losey
authors.forename: Erin J
authors.initials: EJ
authors.lastname: Yee
authors.forename: Anthony
authors.initials: A
authors.lastname: Bernhardt
authors.forename: Vincent
authors.initials: V
authors.lastname: Malba
authors.forename: Lee
authors.initials: L
authors.lastname: Evans
authors.forename: Ryan
authors.initials: R
authors.lastname: Sincic
authors.forename: Maythem
authors.initials: M
authors.lastname: Saeed
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Arenson
authors.forename: Steven W
authors.initials: SW
authors.lastname: Hetts
mesh_terms: D002406:Catheterization, Peripheral / Q000295:instrumentation*; D057510:Endovascular Procedures / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D053783:Magnetic Resonance Imaging, Interventional / Q000295:instrumentation*; D008280:Magnetics / Q000295:instrumentation*; D008846:Micromanipulation / Q000295:instrumentation*; D019047:Phantoms, Imaging