title: [CT strategy for patients with suspected acute appendicitis; comparison of conditional and immediate CT].
abstract: OBJECTIVE
  To compare the diagnostic accuracy of conditional CT strategy, i.e. CT if ultrasound findings are negative or inconclusive, with immediate CT strategy for patients with suspected appendicitis.
  
  
  METHODS
  Subanalysis of a prospective multicenter diagnostic accuracy study.
  
  
  METHODS
  Only data of patients with signs of appendicitis based on medical history, physical examination, and laboratory tests were analyzed. All patients underwent both ultrasound and CT. Images of each were read by different observers who were blinded to the results of the other imaging modality. The observer then selected the most likely diagnosis. These diagnoses were compared with the reference standard, i.e. final diagnoses as assigned by an expert panel based on all available data and at least 6 months of follow-up.
  
  
  RESULTS
  A total of 422 patients with suspected appendicitis were included. In 251 patients the final diagnosis was acute appendicitis (59%). In 199 patients (47%), ultrasound findings were inconclusive or negative. Use of conditional CT strategy resulted in correctly identified number of correctly identified patients with appendicitis, i.e. 96% (95% CI 93-98), versus 95% identified by immediate CT (95% CI 91-97). However, conditional CT strategy resulted in more false positive diagnoses compared with immediate CT (39 versus 22), had an accompanying lower specificity of 77% (95% CI 70-83) versus 87% (95% CI 81-91), and a lower positive predictive value of 86% (95% CI 81-90) versus 92% (95% CI 87-95).
  
  
  CONCLUSIONS
  Use of a conditional CT strategy results in exactly the same number of patients with correctly identified acute appendicitis while halving the number of CTs needed. However, conditional strategy results in more false positive diagnoses.
authors.affiliation: *Dit onderzoek werd eerder gepubliceerd in European Radiology (2015;25:2445-52) met als titel 'Comparison of imaging strategies with conditional versus immediate contrast-enhanced computed tomography in patients with clinical suspicion of acute appendicitis'. Afgedrukt met toestemming.
authors.forename: Jasper J
authors.initials: JJ
authors.lastname: Atema
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Gans
authors.forename: Adrienne
authors.initials: A
authors.lastname: van Randen
authors.forename: Wytze
authors.initials: W
authors.lastname: Laméris
authors.forename: H W Wouter
authors.initials: HW
authors.lastname: van Es
authors.forename: Johannes P M
authors.initials: JP
authors.lastname: van Heesewijk
authors.forename: Bert
authors.initials: B
authors.lastname: van Ramshorst
authors.forename: Wim H
authors.initials: WH
authors.lastname: Bouma
authors.forename: Wim
authors.initials: W
authors.lastname: ten Hove
authors.forename: Esteban M
authors.initials: EM
authors.lastname: van Keulen
authors.forename: Marcel G W
authors.initials: MG
authors.lastname: Dijkgraaf
authors.forename: Patrick M M
authors.initials: PM
authors.lastname: Bossuyt
authors.forename: Jaap
authors.initials: J
authors.lastname: Stoker
authors.forename: Marja A
authors.initials: MA
authors.lastname: Boermeester
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001064:Appendicitis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010808:Physical Examination; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014463:Ultrasonography / Q000379:methods*; D055815:Young Adult