title: MRI-guided procedures in various regions of the body using a robotic assistance system in a closed-bore scanner: preliminary clinical experience and limitations.
abstract: OBJECTIVE
  To present the clinical setup and workflow of a robotic assistance system for image-guided interventions in a conventional magnetic resonance imaging (MRI) environment and to report our preliminary clinical experience with percutaneous biopsies in various body regions.
  
  
  METHODS
  The MR-compatible, servo-pneumatically driven, robotic device (Innomotion) fits into the 60-cm bore of a standard MR scanner. The needle placement (n = 25) accuracy was estimated by measuring the 3D deviation between needle tip and prescribed target point in a phantom. Percutaneous biopsies in six patients and different body regions were planned by graphically selecting entry and target points on intraoperatively acquired roadmap MR data.
  
  
  RESULTS
  For insertion depths between 29 and 95 mm, the average 3D needle deviation was 2.2 +/- 0.7 mm (range 0.9-3.8 mm). Patients with a body mass index of up to approximately 30 kg/m(2) fitted into the bore with the device. Clinical work steps and limitations are reported for the various applications. All biopsies were diagnostic and could be completed without any major complications. Median planning and intervention times were 25 (range 20-36) and 44 (36-68) minutes, respectively.
  
  
  CONCLUSIONS
  Preliminary clinical results in a standard MRI environment suggest that the presented robotic device provides accurate guidance for percutaneous procedures in various body regions. Shorter procedure times may be achievable by optimizing technical and workflow aspects.
authors.affiliation: Department of Diagnostic and Interventional Radiology, Leipzig University Hospital, Leipzig, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Moche
authors.forename: Dirk
authors.initials: D
authors.lastname: Zajonz
authors.forename: Thomas
authors.initials: T
authors.lastname: Kahn
authors.forename: Harald
authors.initials: H
authors.lastname: Busse
mesh_terms: D000328:Adult; D000368:Aged; D001707:Biopsy, Needle / Q000295:instrumentation* / Q000379:methods*; D015992:Body Mass Index; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D012371:Robotics; D025321:Surgery, Computer-Assisted