title: Vascular guide wire navigation with a magnetic guidance system: experimental results in a phantom.
abstract: OBJECTIVE
  To investigate the efficacy of a second-generation prototype magnetic guidance system in complex vessel phantoms versus conventional navigation in simulated interventional radiology procedures and to analyze procedure and fluoroscopy times.
  
  
  METHODS
  The magnetic guidance system consists of two focused-field permanent magnets on each side of the body that create a 0.1-T navigation field and is integrated with a modified C-arm single-planar digital angiography system. Forty-nine navigations in a glass phantom and 80 navigations in a three-dimensional liver phantom were performed with a magnetically tipped floppy 0.014-inch guide wire and a conventional 0.014-inch microcatheter system. Rates of success and fluoroscopy and procedure times were quantified for both techniques. For the liver phantom experiment, the Mann-Whitney U test was used. For the glass phantom experiment, the Wilcoxon matched pair test was used with the Hodges-Lehmann estimator.
  
  
  RESULTS
  In the glass phantom experiments, 42 of 49 turns were successfully performed with both methods. Procedure time to reach a target did not differ significantly between methods, while fluoroscopy time was significantly different when compared with that of the magnetic guidance system (P <.01). Navigation in the liver phantom was successful in 80 of 80 turns with the magnetic guidance system and in 76 of 80 turns with conventional navigation. With the support of the magnetic guidance system, procedure time and fluoroscopy time were significantly different from those with conventional navigation (P <.001).
  
  
  CONCLUSIONS
  The magnetic guidance system allows the precise navigation of a magnetic guide wire in complex vessel phantoms with significantly shorter fluoroscopy and procedure times.
authors.affiliation: Institute of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Johann Wolfgang Goethe-University, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany. m.schiemann@vff.uni-frankfurt.de
authors.forename: Mirko
authors.initials: M
authors.lastname: Schiemann
authors.forename: Reinmar
authors.initials: R
authors.lastname: Killmann
authors.forename: Martin
authors.initials: M
authors.lastname: Kleen
authors.forename: Nasreddin
authors.initials: N
authors.lastname: Abolmaali
authors.forename: Jennifer
authors.initials: J
authors.lastname: Finney
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Vogl
mesh_terms: D015901:Angiography, Digital Subtraction / Q000295:instrumentation; D002404:Catheterization; D004867:Equipment Design; D005471:Fluoroscopy; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D021621:Imaging, Three-Dimensional / Q000295:instrumentation*; D008099:Liver / Q000098:blood supply; D008280:Magnetics / Q000295:instrumentation*; D019060:Minimally Invasive Surgical Procedures / Q000295:instrumentation*; D008955:Models, Cardiovascular; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D025321:Surgery, Computer-Assisted / Q000295:instrumentation*; D013673:Technology Assessment, Biomedical; D014584:User-Computer Interface