title: Low-dose computed tomography versus plain abdominal radiography in the investigation of an acute abdomen.
abstract: BACKGROUND
  To compare low-dose abdominal computed tomography (LDCT) with plain abdominal radiography (AR) in the primary investigation of acute abdominal pain to determine if there is a difference in diagnostic yield, the number of additional investigations required and hospital length of stay (LOS).
  
  
  METHODS
  This randomized controlled trial was approved by the institutional review board, and informed consent was obtained. Patients presenting to the emergency department with an acute abdomen and who would normally be investigated with AR were randomized to either AR or LDCT. The estimated radiation dose of the LDCT protocol was 2-3 mSv compared to 1.1 mSv for AR. Pearson's chi-square and the independent samples t-test were used for the statistical analysis.
  
  
  RESULTS
  A total of 142 patients were eligible, and after exclusions and omitting those with incomplete data, 55 patients remained for analysis in the AR arm and 53 in the LDCT arm. A diagnosis could be obtained in 12 (21.8%) patients investigated with AR compared to 34 (64.2%) for LDCT (P < 0.001). Twenty-eight (50.9%) patients in the AR group required further imaging during their admission compared to 14 (26.4%) in the LDCT group (P= 0.009). There was no difference in the median hospital LOS (3.84 days for AR versus 4.24 days for LDCT, P= 0.83).
  
  
  CONCLUSIONS
  LDCT demonstrates a superior diagnostic yield over AR and reduces the number of subsequent imaging tests for a minimal cost in radiation exposure. However, there is no difference in the overall hospital LOS between the two imaging strategies.
authors.affiliation: Department of Radiology, Royal Perth Hospital, Perth, Western Australia. long.nguyen@health.wa.gov.au
authors.forename: Long K
authors.initials: LK
authors.lastname: Nguyen
authors.forename: Daniel D
authors.initials: DD
authors.lastname: Wong
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Fatovich
authors.forename: Justin M
authors.initials: JM
authors.lastname: Yeung
authors.forename: Jennifer
authors.initials: J
authors.lastname: Persaud
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Wood
authors.forename: David
authors.initials: D
authors.lastname: de Vos
authors.forename: Richard M
authors.initials: RM
authors.lastname: Mendelson
mesh_terms: D000006:Abdomen, Acute / Q000000981:diagnostic imaging* / Q000209:etiology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007415:Intestinal Obstruction / Q000150:complications / Q000000981:diagnostic imaging; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D011027:Pneumoperitoneum / Q000150:complications / Q000000981:diagnostic imaging; D011829:Radiation Dosage; D011860:Radiography, Abdominal; D012680:Sensitivity and Specificity