title: Perforated versus nonperforated acute appendicitis: accuracy of multidetector CT detection.
abstract: OBJECTIVE
  To retrospectively evaluate the accuracy of multidetector computed tomography (CT) in the diagnosis of perforated acute appendicitis by using surgery and pathologic examination combined as the reference standard.
  
  
  METHODS
  The study was institutional review board approved and HIPAA compliant. Informed patient consent was waived. The authors retrospectively identified 244 patients (150 male, 94 female; mean age, 32.8 years; age range, 4-83 years) with pathologically proved acute appendicitis who underwent abdominopelvic multidetector CT. Two radiologists reviewed in consensus the multidetector CT images obtained in all patients for various findings that may be associated with appendiceal perforation. For continuous variables, a comparison of means between the perforated and nonperforated groups was performed by using the Wilcoxon rank sum test. For categorical variables, the sensitivity and specificity of each CT finding for the diagnosis of perforated appendicitis were determined.
  
  
  RESULTS
  The CT findings of abscess (99%), extraluminal gas (98%), and ileus (93%) had the highest specificities for appendiceal perforation; however, the sensitivities of these findings were low: 34%, 35%, and 53%, respectively. The appendix was larger in patients with perforated appendicitis: The mean diameter was 15.1 mm compared with a mean diameter of 11.7 mm in patients with nonperforated appendicitis (P < .001). Appendicolith, free fluid, enlarged abdominal lymph nodes, and enhancement defect in the appendiceal wall were neither highly sensitive nor highly specific for the detection of perforation.
  
  
  CONCLUSIONS
  Although certain multidetector CT findings are very specific for the diagnosis of perforated appendicitis, overall multidetector CT sensitivity is poor. Unless abscess or extraluminal gas is present, multidetector CT cannot enable the diagnosis of perforation.
authors.affiliation: Division of Body Imaging, Department of Radiology, Boston University Medical Center, Boston, MA 02115, USA. sarah.bixby@childrens.harvard.edu
authors.forename: Sarah D
authors.initials: SD
authors.lastname: Bixby
authors.forename: Brian C
authors.initials: BC
authors.lastname: Lucey
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Soto
authors.forename: Jens M
authors.initials: JM
authors.lastname: Theysohn
authors.forename: Jens M
authors.initials: JM
authors.lastname: Theyson
authors.forename: Al
authors.initials: A
authors.lastname: Ozonoff
authors.forename: Jose C
authors.initials: JC
authors.lastname: Varghese
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001064:Appendicitis / Q000000981:diagnostic imaging*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007416:Intestinal Perforation / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*