title: Enteral contrast in the computed tomography diagnosis of appendicitis: comparative effectiveness in a prospective surgical cohort.
abstract: OBJECTIVE
  Our goal was to perform a comparative effectiveness study of intravenous (IV)-only versus IV + enteral contrast in computed tomographic (CT) scans performed for patients undergoing appendectomy across a diverse group of hospitals.
  
  
  BACKGROUND
  Small randomized trials from tertiary centers suggest that enteral contrast does not improve diagnostic performance of CT for suspected appendicitis, but generalizability has not been demonstrated. Eliminating enteral contrast may improve efficiency, patient comfort, and safety.
  
  
  METHODS
  We analyzed data for adult patients who underwent nonelective appendectomy at 56 hospitals over a 2-year period. Data were obtained directly from patient charts by trained abstractors. Multivariate logistic regression was utilized to adjust for potential confounding. The main outcome measure was concordance between final radiology interpretation and final pathology report.
  
  
  RESULTS
  A total of 9047 adults underwent appendectomy and 8089 (89.4%) underwent CT, 54.1% of these with IV contrast only and 28.5% with IV + enteral contrast. Pathology findings correlated with radiographic findings in 90.0% of patients who received IV + enteral contrast and 90.4% of patients scanned with IV contrast alone. Hospitals were categorized as rural or urban and by their teaching status. Regardless of hospital type, there was no difference in concordance between IV-only and IV + enteral contrast. After adjusting for age, sex, comorbid conditions, weight, hospital type, and perforation, odds ratio of concordance for IV + enteral contrast versus IV contrast alone was 0.95 (95% CI: 0.72-1.25).
  
  
  CONCLUSIONS
  Enteral contrast does not improve CT evaluation of appendicitis in patients undergoing appendectomy. These broadly generalizable results from a diverse group of hospitals suggest that enteral contrast can be eliminated in CT scans for suspected appendicitis.
authors.affiliation: *Departments of Surgery †Radiology-University of Washington Medical Center ‡University of Washington Surgical Outcomes Research Center (SORCE) §Swedish Medical Center ¶Virginia Mason Medical Center ∥Surgical Care and Outcomes Assessment Program (SCOAP) and Clinical Effectiveness Research Translation Network (CERTAIN), Seattle, WA **Skagit Valley Hospital, Mount Vernon, WA ††Denver Health Medical Center, Denver, CO ‡‡Department of Surgery, Madigan Army Medical Center, Fort Lewis, WA.
authors.forename: Frederick Thurston
authors.initials: FT
authors.lastname: Drake
authors.forename: Rafael
authors.initials: R
authors.lastname: Alfonso
authors.forename: Puneet
authors.initials: P
authors.lastname: Bhargava
authors.forename: Carlos
authors.initials: C
authors.lastname: Cuevas
authors.forename: Manjiri K
authors.initials: MK
authors.lastname: Dighe
authors.forename: Michael G
authors.initials: MG
authors.lastname: Florence
authors.forename: Morris G
authors.initials: MG
authors.lastname: Johnson
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Jurkovich
authors.forename: Scott R
authors.initials: SR
authors.lastname: Steele
authors.forename: Rebecca Gaston
authors.initials: RG
authors.lastname: Symons
authors.forename: Richard C
authors.initials: RC
authors.lastname: Thirlby
authors.forename: David R
authors.initials: DR
authors.lastname: Flum
mesh_terms: D000328:Adult; D001062:Appendectomy; D001064:Appendicitis / Q000000981:diagnostic imaging* / Q000601:surgery*; D057186:Comparative Effectiveness Research; D003287:Contrast Media; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media