title: Real-Time MRI-Guided Cardiac Cryo-Ablation: A Feasibility Study.
abstract: MRI-based ablation provides an attractive capability of seeing ablation-related tissue changes in real time. Here we describe a real-time MRI-based cardiac cryo-ablation system.
  
  
  
  Studies were performed in canine model (n = 4) using MR-compatible cryo-ablation devices built for animal use: focal cryo-catheter with 8 mm tip and 28 mm diameter cryo-balloon. The main steps of MRI-guided cardiac cryo-ablation procedure (real-time navigation, confirmation of tip-tissue contact, confirmation of vessel occlusion, real-time monitoring of a freeze zone formation, and intra-procedural assessment of lesions) were validated in a 3 Tesla clinical MRI scanner.
  
  
  
  The MRI compatible cryo-devices were advanced to the right atrium (RA) and right ventricle (RV) and their position was confirmed by real-time MRI. Specifically, contact between catheter tip and myocardium and occlusion of superior vena cava (SVC) by the balloon was visually validated. Focal cryo-lesions were created in the RV septum. Circumferential ablation of SVC-RA junction with no gaps was achieved using the cryo-balloon. Real-time visualization of freeze zone formation was achieved in all studies when lesions were successfully created. The ablations and presence of collateral damage were confirmed by T1-weighted and late gadolinium enhancement MRI and gross pathological examination.
  
  
  
  This study confirms the feasibility of a MRI-based cryo-ablation system in performing cardiac ablation procedures. The system allows real-time catheter navigation, confirmation of catheter tip-tissue contact, validation of vessel occlusion by cryo-balloon, real-time monitoring of a freeze zone formation, and intra-procedural assessment of ablations including collateral damage.
authors: CARMA Center, Division of Cardiology, Salt Lake City, Utah, USA.|UCAIR, Department of Radiology, University of Utah, Salt Lake City, Utah, USA.
authors: Eugene G
authors: EG
authors: Kholmovski
authors: Medtronic CryoCath LP, Pointe-Claire, Canada.
authors: Nicolas
authors: N
authors: Coulombe
authors: CARMA Center, Division of Cardiology, Salt Lake City, Utah, USA.|Bioengineering, University of Utah, Salt Lake City, Utah, USA.
authors: Joshua
authors: J
authors: Silvernagel
authors: CARMA Center, Division of Cardiology, Salt Lake City, Utah, USA.|Bioengineering, University of Utah, Salt Lake City, Utah, USA.
authors: Nathan
authors: N
authors: Angel
authors: CARMA Center, Division of Cardiology, Salt Lake City, Utah, USA.|UCAIR, Department of Radiology, University of Utah, Salt Lake City, Utah, USA.
authors: Dennis
authors: D
authors: Parker
authors: CARMA Center, Division of Cardiology, Salt Lake City, Utah, USA.|Bioengineering, University of Utah, Salt Lake City, Utah, USA.
authors: Rob
authors: R
authors: Macleod
authors: CARMA Center, Division of Cardiology, Salt Lake City, Utah, USA.
authors: Nassir
authors: N
authors: Marrouche
authors: CARMA Center, Division of Cardiology, Salt Lake City, Utah, USA.|Bioengineering, University of Utah, Salt Lake City, Utah, USA.
authors: Ravi
authors: R
authors: Ranjan
mesh_terms: D000818:Animals; D062906:Cardiac Catheters; D003452:Cryosurgery / Q000295:instrumentation / Q000379:methods*; D004285:Dogs; D004867:Equipment Design; D005240:Feasibility Studies; D006325:Heart Atria / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D053783:Magnetic Resonance Imaging, Interventional; D023421:Models, Animal; D009206:Myocardium / Q000473:pathology; D011237:Predictive Value of Tests; D013997:Time Factors; D014683:Vena Cava, Superior / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*
keywords: cryo-ablation; cryo-balloon; real-time MRI