title: Appendicolith revealed on CT in children with suspected appendicitis: how specific is it in the diagnosis of appendicitis?
abstract: OBJECTIVE
  The purpose of this study was to determine the sensitivity, specificity, and positive and negative predictive values of a diagnosis of appendicitis when CT without enteric contrast material reveals an appendicolith in children with suspected appendicitis.
  
  
  METHODS
  A retrospective review of children who underwent abdominal CT for suspected appendicitis over a 25-month period was performed to identify patients with an appendicolith. An age-matched group of patients examined for trauma served as controls.
  
  
  RESULTS
  CT was performed in 104 children. Appendicitis was present in 60 (58%) of 104 children; 39 (65%) of 60 had an appendicolith. Appendicitis was not present in 44 (42%) of 104; six (14%) of 44 had an appendicolith. An appendicolith detected on CT had a sensitivity of 65% and a specificity of 86% for the radiologist diagnosing appendicitis. An appendicolith had a positive predictive value of 74% and a negative predictive value of 26%. Among the control population, two (3%) of 74 children had an appendicolith. This number was statistically significant compared with children in the study group with an appendicolith and abdominal pain, but without appendicitis (p = 0.02).
  
  
  CONCLUSIONS
  Although an appendicolith is significantly associated with appendicitis, the detection of an isolated appendicolith on CT is not sufficiently specific to be the sole basis for the diagnosis of acute appendicitis.
authors.affiliation: Department of Radiology and Radiological Sciences, Vanderbilt University Children's Hospital and Medical Center, D-1120 Medical Center North, Nashville, TN 37232-2675, USA.
authors.forename: L H
authors.initials: LH
authors.lastname: Lowe
authors.forename: M W
authors.initials: MW
authors.lastname: Penney
authors.forename: L E
authors.initials: LE
authors.lastname: Scheker
authors.forename: R
authors.initials: R
authors.lastname: Perez
authors.forename: S M
authors.initials: SM
authors.lastname: Stein
authors.forename: R M
authors.initials: RM
authors.lastname: Heller
authors.forename: Y
authors.initials: Y
authors.lastname: Shyr
authors.forename: M
authors.initials: M
authors.lastname: Hernanz-Schulman
mesh_terms: D000293:Adolescent; D001064:Appendicitis / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D001065:Appendix / Q000000981:diagnostic imaging / Q000473:pathology; D002137:Calculi / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D011856:Radiographic Image Enhancement; D011858:Radiographic Magnification; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed