title: Ultrasonography is superior to plain radiography in the diagnosis of pneumoperitoneum.
abstract: BACKGROUND
  The aim of this study was to compare plain radiography with abdominal ultrasonography in the detection of pneumoperitoneum.
  
  
  METHODS
  A total of 188 patients with suspected hollow organ perforation were studied. All patients had abdominal ultrasonography, upright chest radiography and left lateral decubitus abdominal radiography examinations. The sensitivity, specificity, positive and negative predictive value, and accuracy of chest and abdominal radiography were compared with that of abdominal ultrasonography.
  
  
  RESULTS
  One hundred and seventy-eight patients underwent laparotomy; 170 patients had hollow organ perforation, five patients had perforated appendicitis and three had acute cholecystitis. In the diagnosis of pneumoperitoneum, ultrasonography had improved sensitivity (92 versus 78 per cent), negative predictive value (39 versus 20 per cent) and accuracy (88 versus 76 per cent), and similar specificity (both 53 per cent) and positive predictive value (95 versus 94 per cent) compared with plain radiography.
  
  
  CONCLUSIONS
  Ultrasonography is more sensitive than plain radiography in the diagnosis of pneumoperitoneum.
authors.affiliation: Departments of Emergency Medicine, Surgery and Imaging Medicine, National Taiwan University Hospital, Taipei, Taiwan. scc@ha.mc.ntu.edu.tw
authors.forename: S-C
authors.initials: SC
authors.lastname: Chen
authors.forename: Z-S
authors.initials: ZS
authors.lastname: Yen
authors.forename: H-P
authors.initials: HP
authors.lastname: Wang
authors.forename: F-Y
authors.initials: FY
authors.lastname: Lin
authors.forename: C-Y
authors.initials: CY
authors.lastname: Hsu
authors.forename: W-J
authors.initials: WJ
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007813:Laparotomy / Q000379:methods; D008297:Male; D008875:Middle Aged; D011027:Pneumoperitoneum / Q000000981:diagnostic imaging* / Q000601:surgery; D011237:Predictive Value of Tests; D011859:Radiography; D012680:Sensitivity and Specificity; D014463:Ultrasonography