title: Robotic-assisted real-time MRI-guided TAVR: from system deployment to in vivo experiment in swine model.
abstract: OBJECTIVE
  Real-time magnetic resonance imaging (rtMRI) guidance provides significant advantages during transcatheter aortic valve replacement (TAVR) as it provides superior real-time visualization and accurate device delivery tracking. However, performing a TAVR within an MRI scanner remains difficult due to a constrained procedural environment. To address these concerns, a magnetic resonance (MR)-compatible robotic system to assist in TAVR deployments was developed. This study evaluates the technical design and interface considerations of an MR-compatible robotic-assisted TAVR system with the purpose of demonstrating that such a system can be developed and executed safely and precisely in a preclinical model.
  
  
  METHODS
  An MR-compatible robotic surgical assistant system was built for TAVR deployment. This system integrates a 5-degrees of freedom (DoF) robotic arm with a 3-DoF robotic valve delivery module. A user interface system was designed for procedural planning and real-time intraoperative manipulation of the robot. The robotic device was constructed of plastic materials, pneumatic actuators, and fiber-optical encoders.
  
  
  RESULTS
  The mechanical profile and MR compatibility of the robotic system were evaluated. The system-level error based on a phantom model was 1.14 ± 0.33 mm. A self-expanding prosthesis was successfully deployed in eight Yorkshire swine under rtMRI guidance. Post-deployment imaging and necropsy confirmed placement of the stent within 3 mm of the aortic valve annulus.
  
  
  CONCLUSIONS
  These phantom and in vivo studies demonstrate the feasibility and advantages of robotic-assisted TAVR under rtMRI guidance. This robotic system increases the precision of valve deployments, diminishes environmental constraints, and improves the overall success of TAVR.
authors.affiliation: Cardiothoracic Surgery Research Program, National Heart, Lung and Blood Institute, National Institutes of Health, Building 10, Room B1D47, MSC 1550, 10 Center Drive, Bethesda, MD, 20892, USA.
authors.forename: Joshua L
authors.identifier: http://orcid.org/0000-0001-7220-561X
authors.initials: JL
authors.lastname: Chan
authors.affiliation: Cardiothoracic Surgery Research Program, National Heart, Lung and Blood Institute, National Institutes of Health, Building 10, Room B1D47, MSC 1550, 10 Center Drive, Bethesda, MD, 20892, USA.
authors.forename: Dumitru
authors.initials: D
authors.lastname: Mazilu
authors.affiliation: Cardiothoracic Surgery Research Program, National Heart, Lung and Blood Institute, National Institutes of Health, Building 10, Room B1D47, MSC 1550, 10 Center Drive, Bethesda, MD, 20892, USA.
authors.forename: Justin G
authors.initials: JG
authors.lastname: Miller
authors.affiliation: Cardiothoracic Surgery Research Program, National Heart, Lung and Blood Institute, National Institutes of Health, Building 10, Room B1D47, MSC 1550, 10 Center Drive, Bethesda, MD, 20892, USA.
authors.forename: Timothy
authors.initials: T
authors.lastname: Hunt
authors.affiliation: Cardiothoracic Surgery Research Program, National Heart, Lung and Blood Institute, National Institutes of Health, Building 10, Room B1D47, MSC 1550, 10 Center Drive, Bethesda, MD, 20892, USA.
authors.forename: Keith A
authors.initials: KA
authors.lastname: Horvath
authors.affiliation: Cardiothoracic Surgery Research Program, National Heart, Lung and Blood Institute, National Institutes of Health, Building 10, Room B1D47, MSC 1550, 10 Center Drive, Bethesda, MD, 20892, USA. lim2@mail.nih.gov.
authors.forename: Ming
authors.initials: M
authors.lastname: Li
mesh_terms: D000818:Animals; D001021:Aortic Valve / Q000000981:diagnostic imaging / Q000601:surgery*; D005471:Fluoroscopy; D006350:Heart Valve Prosthesis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019047:Phantoms, Imaging; D011474:Prosthesis Design; D065287:Robotic Surgical Procedures / Q000379:methods*; D015607:Stents; D025321:Surgery, Computer-Assisted / Q000379:methods*; D013552:Swine; D065467:Transcatheter Aortic Valve Replacement / Q000379:methods*
keywords: Cardiac surgery; MRI; Magnetic resonance; Robotic assistance; TAVR; Valve replacement