title: Preliminary study on evaluation of the pancreatic tail observable limit of transabdominal ultrasonography using a position sensor and CT-fusion image.
abstract: OBJECTIVE
  Transabdominal ultrasonography (US) is commonly used for the initial screening of bilio-pancreatic diseases in Asian countries due to its widespread availability, the non-invasiveness and the cost-effectiveness. However, it is considered that US has limits to observe the area, namely the blind area. The observation of the pancreatic tail is particularly difficult. The goal of this study was to examine the pancreatic tail region that cannot be visualized on transverse scanning of the upper abdomen using US with spatial positional information and factors related to visualization, and observation of the tail from the splenic hilum.
  
  
  METHODS
  Thirty-nine patients with pancreatic/biliary tract disease underwent CT and US with GPS-like technology and fusion imaging for measurement of the real pancreatic length and the predicted/real unobservable (PU and RU) length of the pancreatic tail. RU from US on transverse scanning and the real pancreatic length were used to determine the unobservable area (UA: RU/the real pancreatic length). Relationships of RU with physical and hematological variables that might influence visualization of the pancreatic tail were investigated.
  
  
  RESULTS
  The real pancreatic length was 160.9 ± 16.4mm, RU was 41.0 ± 17.8mm, and UA was 25.3 ± 10.4%. RU was correlated with BMI (R=0.446, P=0.004) and waist circumferences (R=0.354, P=0.027), and strongly correlated with PU (R=0.788, P<0.001). The pancreatic tail was visible from the splenic hilum in 22 (56%) subjects and was completely identified in 13 (33%) subjects.
  
  
  CONCLUSIONS
  Combined GPS-like technology with fusion imaging was useful for the objective estimation of the pancreatic blind area.
authors.affiliation: Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Sumi
authors.affiliation: Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Itoh
authors.affiliation: Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kawashima
authors.affiliation: Department of Endoscopy, Nagoya University Hospital, Nagoya, Japan.
authors.forename: Eizaburo
authors.initials: E
authors.lastname: Ohno
authors.affiliation: Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Yuya
authors.initials: Y
authors.lastname: Itoh
authors.affiliation: Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Nakamura
authors.affiliation: Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hiramatsu
authors.affiliation: Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sugimoto
authors.affiliation: Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Daijuro
authors.initials: D
authors.lastname: Hayashi
authors.affiliation: Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Takamichi
authors.initials: T
authors.lastname: Kuwahara
authors.affiliation: Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Tomomasa
authors.initials: T
authors.lastname: Morishima
authors.affiliation: Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Kawai
authors.affiliation: Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Furukawa
authors.affiliation: Department of Endoscopy, Nagoya University Hospital, Nagoya, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Funasaka
authors.affiliation: Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Masanao
authors.initials: M
authors.lastname: Nakamura
authors.affiliation: Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Ryoji
authors.initials: R
authors.lastname: Miyahara
authors.affiliation: Department of Gastroenterology, Second Teaching Hospital, Fujita Health University, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Katano
authors.affiliation: Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Ishigami
authors.affiliation: Department of Gastroenterology, Second Teaching Hospital, Fujita Health University, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Ohmiya
authors.affiliation: Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan; Department of Endoscopy, Nagoya University Hospital, Nagoya, Japan.
authors.forename: Hidemi
authors.initials: H
authors.lastname: Goto
authors.affiliation: Department of Endoscopy, Nagoya University Hospital, Nagoya, Japan. Electronic address: hirooka@med.nagoya-u.ac.jp.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Hirooka
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001660:Biliary Tract Diseases / Q000000981:diagnostic imaging; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000295:instrumentation; D010182:Pancreatic Diseases / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000295:instrumentation; D014463:Ultrasonography
keywords: Blind area of pancreas image; Fusion image of CT and US; GPS-like technology; Transabdominal ultrasonography (US)