Imaging strategies for detection of urgent conditions in patients with acute abdominal pain: diagnostic accuracy study.
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.
Laméris
Wytze
W
Department of Surgery, Academic Medical Center, Amsterdam, Netherlands.
van Randen
Adrienne
A
van Es
H Wouter
HW
van Heesewijk
Johannes P M
JP
van Ramshorst
Bert
B
Bouma
Wim H
WH
ten Hove
Wim
W
van Leeuwen
Maarten S
MS
van Keulen
Esteban M
EM
Dijkgraaf
Marcel G W
MG
Bossuyt
Patrick M M
PM
Boermeester
Marja A
MA
Stoker
Jaap
J
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