title: The accordion sign at CT: a nonspecific finding in patients with colonic edema.
abstract: OBJECTIVE
  To determine whether the "accordion sign" is a specific computed tomographic (CT) sign of Clostridium difficile colitis.
  
  
  METHODS
  Fifty-seven patients with CT evidence of severe colitis, as judged by colonic wall thickening, an abnormal haustral pattern, the target sign, and stranding of the pericolic fat, were identified from a computerized CT database for 25 months. CT images were retrospectively evaluated for the presence of oral contrast material in the colon and for the accordion sign. The medical and laboratory records of all patients were reviewed and correlated with CT findings to establish the cause of colitis.
  
  
  RESULTS
  Oral contrast material had reached the colon in 35 of 57 patients at the time of the CT examination. The images in 15 of these patients demonstrated the accordion sign, and those in 20 patients did not. C difficile colitis was documented in four of the 15 cases displaying the accordion sign. In the remaining 11 patients, a different cause was documented. Oral contrast material had not reached the colon in the remaining 22 patients. Within this group with findings similar to the accordion sign, five patients had documented C difficile colitis, and four had colitis from other causes.
  
  
  CONCLUSIONS
  The accordion sign is indicative of severe colonic edema or inflammation, but it is not specific for C difficile colitis.
authors.affiliation: Department of Radiology, NYU Medical Center, Tisch Hospital 10016, USA.
authors.forename: M
authors.initials: M
authors.lastname: Macari
authors.forename: E J
authors.initials: EJ
authors.lastname: Balthazar
authors.forename: A J
authors.initials: AJ
authors.lastname: Megibow
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003106:Colon / Q000000981:diagnostic imaging*; D003108:Colonic Diseases / Q000000981:diagnostic imaging*; D003287:Contrast Media; D004487:Edema / Q000000981:diagnostic imaging*; D004761:Enterocolitis, Pseudomembranous / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media