title: A deflectable guiding catheter for real-time MRI-guided interventions.
abstract: OBJECTIVE
  To design a deflectable guiding catheter that omits long metallic components yet preserves mechanical properties to facilitate therapeutic interventional MRI procedures.
  
  
  METHODS
  The catheter shaft incorporated Kevlar braiding. A 180° deflection was attained with a 5-cm nitinol slotted tube, a nitinol spring, and a Kevlar pull string. We tested three designs: passive, passive incorporating an inductively coupled coil, and active receiver. We characterized mechanical properties, MRI properties, RF induced heating, and in vivo performance in swine.
  
  
  RESULTS
  Torque and tip deflection force were satisfactory. Representative procedures included hepatic and azygos vein access, laser cardiac septostomy, and atrial septal defect crossing. Visualization was best in the active configuration, delineating profile and tip orientation. The passive configuration could be used in tandem with an active guidewire to overcome its limited conspicuity. There was no RF-induced heating in all configurations under expected use conditions in vitro and in vivo.
  
  
  CONCLUSIONS
  Kevlar and short nitinol component substitutions preserved mechanical properties. The active design offered the best visibility and usability but reintroduced metal conductors. We describe versatile deflectable guiding catheters with a 0.057" lumen for interventional MRI catheterization. Implementations are feasible using active, inductive, and passive visualization strategies to suit application requirements.
authors: Cardiovascular and Pulmonary Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA.
authors: Jamie A
authors: JA
authors: Bell
authors: Christina E
authors: CE
authors: Saikus
authors: Kanishka
authors: K
authors: Ratnayaka
authors: Vincent
authors: V
authors: Wu
authors: Merdim
authors: M
authors: Sonmez
authors: Anthony Z
authors: AZ
authors: Faranesh
authors: Jessica H
authors: JH
authors: Colyer
authors: Robert J
authors: RJ
authors: Lederman
authors: Ozgur
authors: O
authors: Kocaturk
mesh_terms: D000818:Animals; D006328:Cardiac Catheterization / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006321:Heart / Q000033:anatomy & histology*; D053783:Magnetic Resonance Imaging, Interventional / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine