title: Integrated neuronavigation system with intraoperative image updating.
abstract: OBJECTIVE
  Recently, MRI has entered the field of image-guided surgery as a new intraoperative imaging modality. In spite of its obvious benefits, this type of iMRI scanner has some drawbacks that have limited its utilization. The goal of the work presented here was to overcome some of these disadvantages.
  
  
  METHODS
  A system that allows intraoperative images to be acquired during surgery and have the ability to conduct surgery outside the constraints of the narrow gap of the open magnet was implemented. Ability to conduct tasks inside the scanner with real-time image guidance was also maintained. The system allowed navigation with neuronavigation tools both inside the gap of an open magnet and outside the magnet, utilizing two different optical camera-sets and a dynamic reference frame. Automatic patient registration was implemented.
  
  
  RESULTS
  The average difference between tracking position measured outside and inside the magnet was 0.8 +/- 0.1 mm.
  
  
  CONCLUSIONS
  In the work presented in this note we have introduced a dynamic reference frame to compensate for transport of the patient to a location outside the scanner employing a second camera set. The integrated system showed adequate accuracy.
authors.affiliation: The Interventional Centre, Rikshospitalet, University Hospital, Oslo, Norway. eigil.samset@rikshospitalet.no
authors.forename: E
authors.initials: E
authors.lastname: Samset
authors.forename: J O
authors.initials: JO
authors.lastname: Høgetveit
authors.forename: G T
authors.initials: GT
authors.lastname: Cate
authors.forename: H
authors.initials: H
authors.lastname: Hirschberg
mesh_terms: D004867:Equipment Design; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D038361:Neuronavigation / Q000295:instrumentation*; D015203:Reproducibility of Results; D025321:Surgery, Computer-Assisted / Q000295:instrumentation*; D014584:User-Computer Interface