title: Image Registered Gastroscopic Ultrasound (IRGUS) in human subjects: a pilot study to assess feasibility.
abstract: OBJECTIVE
  Endoscopic ultrasound (EUS) is a complex procedure due to the subtleties of ultrasound interpretation, the small field of observation, and the uncertainty of probe position and orientation. Animal studies demonstrated that Image Registered Gastroscopic Ultrasound (IRGUS) is feasible and may be superior to conventional EUS in efficiency and image interpretation. This study explores whether these attributes of IRGUS will be evident in human subjects, with the aim of assessing the feasibility, effectiveness, and efficiency of IRGUS in patients with suspected pancreatic lesions.
  
  
  METHODS
  This was a prospective feasibility study at a tertiary care academic medical center in human patients with pancreatic lesions on computed tomography (CT) scan. Patients who were scheduled to undergo conventional EUS were randomly chosen to undergo their procedure with IRGUS. Main outcome measures included feasibility, ease of use, system function, validated task load (TLX) assessment instrument, and IRGUS experience questionnaire.
  
  
  RESULTS
  Five patients underwent IRGUS without complication. Localization of pancreatic lesions was accomplished efficiently and accurately (TLX temporal demand 3.7 %; TLX effort 8.6 %). Image synchronization and registration was accomplished in real time without procedure delay. The mean assessment score for endoscopist experience with IRGUS was positive (66.6 ± 29.4). Real-time display of CT images in the EUS plane and echoendoscope orientation were the most beneficial characteristics.
  
  
  CONCLUSIONS
  IRGUS appears feasible and safe in human subjects, and efficient and accurate at identification of probe position and image interpretation. IRGUS has the potential to broaden the adoption of EUS techniques and shorten EUS learning curves. Clinical studies comparing IRGUS with conventional EUS are ongoing.
authors.affiliation: Division of Gastroenterology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
authors.forename: K L
authors.initials: KL
authors.lastname: Obstein
authors.forename: R S
authors.initials: RS
authors.lastname: Estépar
authors.forename: J
authors.initials: J
authors.lastname: Jayender
authors.forename: V D
authors.initials: VD
authors.lastname: Patil
authors.forename: I S
authors.initials: IS
authors.lastname: Spofford
authors.forename: M B
authors.initials: MB
authors.lastname: Ryan
authors.forename: B I
authors.initials: BI
authors.lastname: Lengyel
authors.forename: R
authors.initials: R
authors.lastname: Shams
authors.forename: K G
authors.initials: KG
authors.lastname: Vosburgh
authors.forename: C C
authors.initials: CC
authors.lastname: Thompson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016145:Endoscopy, Digestive System / Q000379:methods; D019160:Endosonography / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D010182:Pancreatic Diseases / Q000175:diagnosis / Q000000981:diagnostic imaging*; D010865:Pilot Projects; D011446:Prospective Studies