title: Therapeutic impact of CT of the appendix in a community hospital emergency department.
abstract: OBJECTIVE
  The purpose of this study was to prospectively evaluate the therapeutic impact of CT of the appendix in a community hospital.
  
  
  METHODS
  For each of 100 consecutive adult patients who presented to a community hospital emergency department from August 2006 to November 2006 and underwent CT of the appendix, the proposed treatment plan and the likelihood of appendicitis were recorded before CT and were compared with the actual treatment after CT. The primary outcome assessed was change in patient management after CT. The percentage likelihood of appendicitis, whether patient disposition changed after CT, and the presence or absence of appendicitis were examined. The accuracy of CT was also calculated.
  
  
  RESULTS
  The treatment plans of the emergency clinicians changed in 29 patients (29%). Appendicitis was ruled out on the basis of CT findings in 50% (9/18) of patients when appendicitis was considered probable and in 60% (3/5) when appendicitis was considered very likely. When appendicitis was considered unlikely, appendicitis was ruled out by CT in 100% (20/20) of patients. CT of the appendix was shown to have high sensitivity (94%), specificity (100%), positive predictive value (100%), negative predictive value (99%), and accuracy (99%).
  
  
  CONCLUSIONS
  CT of the appendix had an important therapeutic impact on patients presenting to a community hospital emergency department. The data suggest that CT can be withheld in patients in whom emergency clinicians rate the likelihood of appendicitis as unlikely but that CT findings are often of benefit even when appendicitis is judged to be very likely.
authors.affiliation: Department of Radiology, University of Washington, Harborview Medical Center, 325 Ninth Ave., Box 359728, Seattle, WA 98104-2499, USA. ronathan@u.washington.edu
authors.forename: Robert O
authors.initials: RO
authors.lastname: Nathan
authors.forename: C Craig
authors.initials: CC
authors.lastname: Blackmore
authors.forename: Jeffrey G
authors.initials: JG
authors.lastname: Jarvik
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001064:Appendicitis / Q000000981:diagnostic imaging*; D001065:Appendix / Q000000981:diagnostic imaging*; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007479:Iopamidol; D016013:Likelihood Functions; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted; D011860:Radiography, Abdominal; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007479:Iopamidol