title: Real-time-MR guidance for placement of a self-made fully MR-compatible atrial septal occluder: in vitro test.
abstract: OBJECTIVE
  This in vitro study investigated the feasibility to visualize the placement of three different atrial septal occluder systems using real-time MR control.
  
  
  METHODS
  The experiments were performed on an interventional 1.5 T high field whole body system. Real-time MR imaging was achieved by radial or spiral k-space filling in conjunction with the sliding window reconstruction technique yielding an imaging speed of 15 frames per second. The CardioSeal, Amplatzer Septal Occluder and a specially designed MR-compatible closure device were tested in a water bath. A punctured plastic wall served as model for the atrial septal defect.
  
  
  RESULTS
  The delivery systems of the CardioSeal and Amplatzer Occluder were ferromagnetic and caused substantial artifacts, making the device placement impossible, even if the magnetic forces would have been acceptable. The self-made prototype caused only minor susceptibility artifacts allowing its visualization on the MR images. The MR imaging techniques applied enabled real-time control of the occluder including steering through the artificial septal foramen and visualization of the occluder deployment.
  
  
  CONCLUSIONS
  Real-time MR imaging allows for guidance and placement of an MR-compatible septal occluder in vitro suggesting the feasibility to perform atrial septal occlusion under MR-guidance in vivo as well.
authors.affiliation: Clinic of Diagnostic Radiology, University of Technology Aachen, Germany. buecker@rad.rwth-aachen.de
authors.forename: A
authors.initials: A
authors.lastname: Buecker
authors.forename: E
authors.initials: E
authors.lastname: Spuentrup
authors.forename: R
authors.initials: R
authors.lastname: Grabitz
authors.forename: F
authors.initials: F
authors.lastname: Freudenthal
authors.forename: T
authors.initials: T
authors.lastname: Schaeffter
authors.forename: J J
authors.initials: JJ
authors.lastname: van Vaals
authors.forename: W
authors.initials: W
authors.lastname: Günther
mesh_terms: D006325:Heart Atria / Q000473:pathology; D006344:Heart Septal Defects, Atrial / Q000628:therapy*; D006346:Heart Septum / Q000473:pathology; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D019047:Phantoms, Imaging; D019919:Prosthesis Implantation