title: EUS with CT improves efficiency and structure identification over conventional EUS.
abstract: BACKGROUND
  EUS is complicated because of the subtleties of US interpretation, small fields of observation, and uncertainty of probe position and orientation.
  
  
  OBJECTIVE
  Improved EUS performance is sought by providing contextual information to support US probe positioning and identification of features in US images. Our aims were to demonstrate the feasibility of the image registered gastroscopic US (IRGUS) system in a porcine model and to compare the effectiveness and the efficiency of IRGUS with traditional EUS.
  
  
  METHODS
  Animal feasibility study.
  
  
  METHODS
  The IRGUS system uses preprocedure CT and miniature US probe trackers to create real-time synthetic displays of the position of the probe tip and a matched slice of CT data for comparison with the US image. Participants used EUS and IRGUS systems in a porcine model to evaluate the speed and accuracy of structure identification.
  
  
  METHODS
  The performance and utility of IRGUS were determined by the number of correctly identified structures in a timed trial, kinematic variables, and a structured survey.
  
  
  RESULTS
  IRGUS was twice as effective as EUS in localizing and identifying individual structures. In timed trials, IRGUS users identified over 25% more structures than EUS users. Improvement in examination efficiency and accuracy of feature identification was statistically significant, and 90% of the users preferred IRGUS to EUS for these tasks.
  
  
  CONCLUSIONS
  IRGUS appears feasible and may be superior to conventional EUS in efficiency and accuracy of probe positioning and in image interpretation. IRGUS has the potential to shorten the EUS learning curve and to broaden the adoption of EUS techniques by gastroenterologists.
authors.affiliation: Center for Integration of Medicine and Innovative Technology, Boston, Massachusetts 02114, USA.
authors.forename: Kirby G
authors.initials: KG
authors.lastname: Vosburgh
authors.forename: Nicholas
authors.initials: N
authors.lastname: Stylopoulos
authors.forename: Raul San Jose
authors.initials: RS
authors.lastname: Estepar
authors.forename: Randy E
authors.initials: RE
authors.lastname: Ellis
authors.forename: Eigil
authors.initials: E
authors.lastname: Samset
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Thompson
mesh_terms: D000818:Animals; D016099:Endoscopy, Gastrointestinal / Q000379:methods; D019160:Endosonography / Q000295:instrumentation*; D023421:Models, Animal; D013552:Swine; D014057:Tomography, X-Ray Computed