title: MRI features associated with acute appendicitis.
abstract: OBJECTIVE
  To identify MRI features associated with appendicitis.
  
  
  METHODS
  Features expected to be associated with appendicitis were recorded in consensus by two expert radiologists on 223 abdominal MRIs in patients with suspected appendicitis. Nine MRI features were studied: appendix diameter >7 mm, appendicolith, peri-appendiceal fat infiltration, peri-appendiceal fluid, absence of gas in the appendix, appendiceal wall destruction, restricted diffusion of the appendiceal wall, lumen or focal fluid collections. Appendicitis was assigned as the final diagnosis in 117/223 patients. Associations between imaging features and appendicitis were evaluated with logistic regression analysis.
  
  
  RESULTS
  All investigated features were significantly associated with appendicitis in univariate analysis. Combinations of two and three features were associated with a probability of appendicitis of 88 % and 92 %, respectively. In patients without any of the nine features, appendicitis was present in 2 % of cases. After multivariate analysis, only an appendix diameter >7 mm, peri-appendiceal fat infiltration and restricted diffusion of the appendiceal wall were significantly associated with appendicitis. The probability of appendicitis was 96 % in their presence and 2 % in their absence.
  
  
  CONCLUSIONS
  An appendix diameter >7 mm, peri-appendiceal fat infiltration and restricted diffusion of the appendiceal wall have the strongest association with appendicitis on MRI.
  
  
  CONCLUSIONS
  • An enlarged appendix, fat infiltration and restricted diffusion are associated with appendicitis. • One such feature on MRI gives an 88 % probability of appendicitis. • Two features in combination give a probability of appendicitis of 94 %. • Combinations of three features give a probability of appendicitis of 96 %. • The absence of these features almost rules out appendicitis (2 %).
authors.affiliation: Department of Surgery, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands, m.m.leeuwenburgh@amc.uva.nl.
authors.forename: Marjolein M N
authors.initials: MM
authors.lastname: Leeuwenburgh
authors.forename: Sebastiaan
authors.initials: S
authors.lastname: Jensch
authors.forename: Jan W C
authors.initials: JW
authors.lastname: Gratama
authors.forename: Aart
authors.initials: A
authors.lastname: Spilt
authors.forename: Bart M
authors.initials: BM
authors.lastname: Wiarda
authors.forename: H Wouter
authors.initials: HW
authors.lastname: Van Es
authors.forename: Lodewijk P J
authors.initials: LP
authors.lastname: Cobben
authors.forename: Patrick M M
authors.initials: PM
authors.lastname: Bossuyt
authors.forename: Marja A
authors.initials: MA
authors.lastname: Boermeester
authors.forename: Jaap
authors.initials: J
authors.lastname: Stoker
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001064:Appendicitis / Q000175:diagnosis*; D001065:Appendix / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D055815:Young Adult