title: Preclinical study of endoscopic ultrasonography with electronic radial scanning echoendoscope.
abstract: BACKGROUND
  To evaluate the imaging possibility of a newly designed electronic radial scanning echoendoscope (ER-ES).
  
  
  METHODS
  In the in vivo study of swine, we obtained B-mode endoscopic ultrasonography (EUS) images of the gastric and gallbladder (GB) walls and checked the ability to detect Doppler signals using ER-ES and electronic linear array echoendoscope (EL-ES). Furthermore, in the ex vivo study of swine, B-mode EUS images of fixed gastric and GB wall specimens were obtained using ER-ES, EL-ES and mechanical radial scanning echoendoscope (MR-ES). In the study of resected human specimens, we obtained B-mode EUS images of five resected GB specimens (three normal GB, one cholecystitis and one cancerous) using the three types of echoendoscope.
  
  
  RESULTS
  In the in vivo study of swine, ER-ES and EL-ES depicted the gastric walls as five-layered, and the GB walls as single-layered structures. The ability to detect Doppler signals was equal between ER-ES and EL-ES. In the ex vivo study of swine, ER-ES, MR-ES and EL-ES equally delineated the gastric walls as five-layered and GB walls as three-layered structures. In the study of resected human specimens, results demonstrated the normal GB walls as three-layered, the cholecystitis as a combination of outer high-echoic and inner low-echoic layers, and the cancer as a protruded tumor.
  
  
  CONCLUSIONS
  We conclude that ER-ES has faculties for making B-mode images as well as EL-ES and MR-ES. In addition, in the in vivo study, ER-ES can analyze blood flow information as well as EL-ES.
authors.affiliation: Second Department of Internal Medicine, Nagoya University School of Medicine, Nagoya, Japan.
authors.forename: Katsushi
authors.initials: K
authors.lastname: Niwa
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Hirooka
authors.forename: Akihiro
authors.initials: A
authors.lastname: Itoh
authors.forename: Senju
authors.initials: S
authors.lastname: Hashimoto
authors.forename: Takanori
authors.initials: T
authors.lastname: Hirai
authors.forename: Kinichi
authors.initials: K
authors.lastname: Takeda
authors.forename: Hidemi
authors.initials: H
authors.lastname: Goto
mesh_terms: D000818:Animals; D019723:Endoscopes; D019160:Endosonography / Q000295:instrumentation*; D004867:Equipment Design; D005704:Gallbladder / Q000000981:diagnostic imaging*; D006801:Humans; D013270:Stomach / Q000000981:diagnostic imaging*; D013552:Swine