title: Intraluminal air within an obstructed appendix: a CT sign of perforated or necrotic appendicitis.
abstract: OBJECTIVE
  The aim of this study was to evaluate the predictive value of intraluminal air for appendiceal necrosis and/or perforation when not apparent on imaging. Additional factors of intraluminal appendicoliths, age, and gender were also assessed.
  
  
  METHODS
  Patients with pathologically proven appendicitis who underwent multidetector computed tomographic imaging over a 3-year period (n = 487) were retrospectively reviewed. Those with imaging evidence for perforation were excluded to create a study population of apparent uncomplicated acute appendicitis (n = 374). Each scan was assessed for intraluminal appendiceal air and appendicoliths on multidetector computed tomography and compared against surgical and pathologic results for appendiceal necrosis and/or perforation.
  
  
  RESULTS
  Image-occult necrosis or perforation was present in 17.4% (65 or 374) of the study cohort. Intraluminal air and appendicoliths were predictive variables by univariate logistic regression (P = .001 and P ≤ .001, respectively), with odds ratios of 2.64 (95% confidence interval, 1.48-4.73) for intraluminal air and 2.67 (95% confidence interval, 1.55-4.61) for appendicoliths. Both remained independent variables on multivariate modeling despite multicollinearity. Increasing age was also predictive (odds ratio, 1.25; 95% confidence interval, 1.09-1.44; P = .002), whereas gender was not (P = .472).
  
  
  CONCLUSIONS
  Intraluminal appendiceal air in the setting of acute appendicitis is a marker of perforated or necrotic appendicitis. Recognition of this finding in otherwise uncomplicated appendicitis at imaging should raise suspicion for image-occult perforation or necrosis.
authors: Mallinckrodt Institute of Radiology, Washington University, St Louis, Missouri, USA.
authors: Joseph T
authors: JT
authors: Azok
authors: David H
authors: DH
authors: Kim
authors: Alejandro
authors: A
authors: Munoz Del Rio
authors: Sushilkumar K
authors: SK
authors: Sonavane
authors: Sanjeev
authors: S
authors: Bhalla
authors: Victor
authors: V
authors: Anaya-Baez
authors: Christine O
authors: CO
authors: Menias
mesh_terms: D000328:Adult; D000388:Air; D001064:Appendicitis / Q000000981:diagnostic imaging* / Q000473:pathology*; D001065:Appendix / Q000000981:diagnostic imaging* / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D009336:Necrosis / Q000000981:diagnostic imaging / Q000473:pathology; D011856:Radiographic Image Enhancement / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult