title: Imaging strategies for detection of urgent conditions in patients with acute abdominal pain: diagnostic accuracy study.
abstract: OBJECTIVE
  To identify an optimal imaging strategy for the accurate detection of urgent conditions in patients with acute abdominal pain.
  
  
  METHODS
  Fully paired multicentre diagnostic accuracy study with prospective data collection.
  
  
  METHODS
  Emergency departments of two university hospitals and four large teaching hospitals in the Netherlands.
  
  
  METHODS
  1021 patients with non-traumatic abdominal pain of >2 hours' and <5 days' duration. Exclusion criteria were discharge from the emergency department with no imaging considered warranted by the treating physician, pregnancy, and haemorrhagic shock.
  
  
  METHODS
  All patients had plain radiographs (upright chest and supine abdominal), ultrasonography, and computed tomography (CT) after clinical and laboratory examination. A panel of experienced physicians assigned a final diagnosis after six months and classified the condition as urgent or non-urgent.
  
  
  METHODS
  Sensitivity and specificity for urgent conditions, percentage of missed cases and false positives, and exposure to radiation for single imaging strategies, conditional imaging strategies (CT after initial ultrasonography), and strategies driven by body mass index and age or by location of pain.
  
  
  RESULTS
  661 (65%) patients had a final diagnosis classified as urgent. The initial clinical diagnosis resulted in many false positive urgent diagnoses, which were significantly reduced after ultrasonography or CT. CT detected more urgent diagnoses than did ultrasonography: sensitivity was 89% (95% confidence interval 87% to 92%) for CT and 70% (67% to 74%) for ultrasonography (P<0.001). A conditional strategy with CT only after negative or inconclusive ultrasonography yielded the highest sensitivity, missing only 6% of urgent cases. With this strategy, only 49% (46% to 52%) of patients would have CT. Alternative strategies guided by body mass index, age, or location of the pain would all result in a loss of sensitivity.
  
  
  CONCLUSIONS
  Although CT is the most sensitive imaging investigation for detecting urgent conditions in patients with abdominal pain, using ultrasonography first and CT only in those with negative or inconclusive ultrasonography results in the best sensitivity and lowers exposure to radiation.
authors: Department of Surgery, Academic Medical Center, Amsterdam, Netherlands.
authors: Wytze
authors: W
authors: Laméris
authors: Adrienne
authors: A
authors: van Randen
authors: H Wouter
authors: HW
authors: van Es
authors: Johannes P M
authors: JP
authors: van Heesewijk
authors: Bert
authors: B
authors: van Ramshorst
authors: Wim H
authors: WH
authors: Bouma
authors: Wim
authors: W
authors: ten Hove
authors: Maarten S
authors: MS
authors: van Leeuwen
authors: Esteban M
authors: EM
authors: van Keulen
authors: Marcel G W
authors: MG
authors: Dijkgraaf
authors: Patrick M M
authors: PM
authors: Bossuyt
authors: Marja A
authors: MA
authors: Boermeester
authors: Jaap
authors: J
authors: Stoker
mesh_terms: D015746:Abdominal Pain / Q000000981:diagnostic imaging / Q000209:etiology*; D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D003952:Diagnostic Imaging / Q000379:methods* / Q000592:standards; D004630:Emergencies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D011859:Radiography; D012680:Sensitivity and Specificity; D014463:Ultrasonography; D055815:Young Adult