title: A prototype of injector to control and to detect the release of magnetic beads within the constraints of multibifurcation magnetic resonance navigation procedures.
abstract: An injector equipped with a bead capture and a bead detection system is presented. In the context of magnetic resonance navigation (MRN), in which MRI gradients are used to steer intravascular therapeutic carriers, fast and reliable injection is essential. In this paper, we present a prototype of injector to control and to detect the release of magnetic beads.
  
  
  
  The injector relies on two distinct subsystems: (1) the capture subsystem, which creates local magnetic force to stop the flow of magnetic beads; and (2) the detection subsystem, which detects flowing beads and generates a trigger signal to start MRI gradient pulses. Both systems rely on small microcoils wound on the tubing.
  
  
  
  Five-turn microcoils show the best compromise between size and performance. Less than 5 mW of power is required to capture 0.8-mm beads moving in a flow above 5 mL min-1or when a gradient above 200 mT m-1is applied. The detection system is not sensitive to noise and detects every 0.8-mm bead in flow rates up to 14 mL m-1.
  
  
  
  The prototype of injector shows performance above the requirements inherent to magnetic resonance navigation. This system is a step toward in vivo multibifurcation MRN. Magn Reson Med 77:444-452, 2017. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Clinical Image Processing Laboratory (LCTI), Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 rue Saint-Denis, Montreal, QC, H2X 0A9, Canada.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Bigot
authors.affiliation: Clinical Image Processing Laboratory (LCTI), Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 rue Saint-Denis, Montreal, QC, H2X 0A9, Canada.|Centre Hospitalier de l'Université de Montréal, Department of Radiology, 1560 Sherbrooke Est, Montreal, QC, CAN, H2L 4M1.
authors.forename: Gilles
authors.initials: G
authors.lastname: Soulez
authors.affiliation: NanoRobotics Laboratory, Department of Computer and Software Engineering and Institute of Biomedical Engineering, Polytechnique Montréal, C.P. 6079, Succursale Centre-ville, Montréal, Québec, Canada, H3C 3A7.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Martel
mesh_terms: D004867:Equipment Design; D007267:Injections / Q000295:instrumentation*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D059346:Magnets; D008863:Microspheres; D008962:Models, Theoretical; D025321:Surgery, Computer-Assisted / Q000379:methods*
keywords: interventional MR; magnetic capture; magnetic carrier detection; magnetic resonance navigation (MRN); magnetic targeting; microcoils