title: Interventional MR elastography for MRI-guided percutaneous procedures.
abstract: OBJECTIVE
  MRI-guided thermal ablations require reliable monitoring methods to ensure complete destruction of the diseased tissue while avoiding damage to the surrounding healthy tissue. Based on the fact that thermal ablations result in substantial changes in biomechanical properties, interventional MR elastography (MRE) dedicated to the monitoring of MR-guided thermal therapies is proposed here.
  
  
  METHODS
  Interventional MRE consists of a needle MRE driver, a fast and interactive gradient echo pulse sequence with motion encoding, and an inverse problem solver in real-time. This complete protocol was tested in vivo on swine and the ability to monitor elasticity changes in real-time was assessed in phantom.
  
  
  RESULTS
  Thanks to a short repetition time, a reduction of the number of phase-offsets and the use of a sliding window, one refreshed elastogram was provided every 2.56 s for an excitation frequency of 100 Hz. In vivo elastograms of swine liver were successfully provided in real-time during one breath-hold. Changes of elasticity were successfully monitored in a phantom during its gelation with the same elastogram frame rate.
  
  
  CONCLUSIONS
  This study demonstrates the ability of detecting elasticity changes in real-time and providing elastograms in vivo with interventional MRE that could be used for the monitoring of thermal ablations.
authors.affiliation: ICube, University of Strasbourg, CNRS, IHU Strasbourg, France.
authors.forename: Nadège
authors.initials: N
authors.lastname: Corbin
authors.affiliation: ICube, University of Strasbourg, CNRS, IHU Strasbourg, France.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Vappou
authors.affiliation: ICube, University of Strasbourg, CNRS, IHU Strasbourg, France.
authors.forename: Elodie
authors.initials: E
authors.lastname: Breton
authors.affiliation: ICube, University of Strasbourg, CNRS, IHU Strasbourg, France.
authors.forename: Quentin
authors.initials: Q
authors.lastname: Boehler
authors.affiliation: ICube, University of Strasbourg, CNRS, IHU Strasbourg, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Barbé
authors.affiliation: ICube, University of Strasbourg, CNRS, IHU Strasbourg, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Renaud
authors.affiliation: ICube, University of Strasbourg, CNRS, IHU Strasbourg, France.
authors.forename: Michel
authors.initials: M
authors.lastname: de Mathelin
mesh_terms: D000465:Algorithms; D000818:Animals; D054459:Elasticity Imaging Techniques / Q000379:methods*; D057510:Endovascular Procedures / Q000379:methods*; D005240:Feasibility Studies; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008099:Liver / Q000098:blood supply / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008954:Models, Biological; D019047:Phantoms, Imaging; D013552:Swine
keywords: MR elastography; interventional radiology; therapy monitoring; thermal ablation