title: Newly-developed, forward-viewing echoendoscope: a comparative pilot study to the standard echoendoscope in the imaging of abdominal organs and feasibility of endoscopic ultrasound-guided interventions.
abstract: OBJECTIVE
  Multiple diagnostic and therapeutic endoscopic ultrasound (EUS) procedures have been widely performed using a standard oblique-viewing (OV) curvilinear array (CLA) echoendoscope. Recently, a new, forward-viewing (FV) CLA was developed, with the advantages of improved endoscopic viewing and manipulation of devices. However, the FV-CLA echoendoscope has a narrower ultrasound scanning field, and lacks an elevator, which might represent obstacles for clinical use. The aim of this study was to compare the FV-CLA echoendoscope to the OV-CLA echoendoscope for EUS imaging of abdominal organs, and to assess the feasibility of EUS-guided interventions using the FV-CLA echoendoscope.
  
  
  METHODS
  EUS examinations were first performed and recorded using the OV-CLA echoendoscope, followed immediately by the FV-CLA echoendoscope. Video recordings were then assessed by two independent endosonographers in a blinded fashion. The EUS visualization and image quality of specific abdominal organs/structures were scored. Any indicated fine-needle aspiration (FNA) or intervention was performed using the FV-CLA echoendoscope, with the OV-CLA echoendoscope as salvage upon failure.
  
  
  RESULTS
  A total of 21 patients were examined in the study. Both echoendoscopes had similar visualization and image quality for all organs/structures, except the common hepatic duct (CHD), which was seen significantly better with the FV-CLA echoendoscope. EUS interventions were conducted in eight patients, including FNA of pancreatic mass (3), pancreatic cyst (3), and cystgastrostomy (2). The FV-CLA echoendoscope was successful in seven patients. One failed FNA of the pancreatic head cyst was salvaged using the OV-CLA echoendoscope.
  
  
  CONCLUSIONS
  There were no differences between the FV-CLA echoendoscope and the OV-CLA echoendoscope in visualization or image quality on upper EUS, except for the superior image quality of CHD using the FV-CLA echoendoscope. Therefore, the disadvantages of the FV-CLA echoendoscope appear minimal in light of the potential advantages.
authors.affiliation: HH Chao Comprehensive Digestive Disease Center, University of California, Irvine Medical Center, Orange, California 92868, USA.
authors.forename: Takuji
authors.initials: T
authors.lastname: Iwashita
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Nakai
authors.forename: John G
authors.initials: JG
authors.lastname: Lee
authors.forename: Do Hyun
authors.initials: DH
authors.lastname: Park
authors.forename: V Raman
authors.initials: VR
authors.lastname: Muthusamy
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Chang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle / Q000295:instrumentation*; D002140:California; D004066:Digestive System Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D019723:Endoscopes; D016145:Endoscopy, Digestive System / Q000295:instrumentation*; D019160:Endosonography / Q000295:instrumentation*; D004867:Equipment Design; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010865:Pilot Projects; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D018084:Ultrasonography, Interventional / Q000295:instrumentation*; D014741:Video Recording