title: Prospective comparison of air-contrast barium enema and colonoscopy in patients with fecal occult blood: a pilot study.
abstract: BACKGROUND
  The utility of air-contrast barium enema and colonoscopy for evaluation of the colon has been debated. Air-contrast barium enema is less expensive and invasive than colonoscopy, but it also is less sensitive and specific. Further, although air-contrast barium enema may be less painful than colonoscopy, it often is poorly tolerated by patients. Thus, this study compared the sensitivity and the specificity of air-contrast barium enema and colonoscopy for detection of colonic lesions in patients with fecal occult blood.
  
  
  METHODS
  Over a 30-month period, patients with fecal occult blood were recruited. Patients underwent standard air-contrast barium enema, followed by colonoscopy 7 to 14 days later. Colonoscopists were blinded to the results of air-contrast barium enema until the colonoscopy was completed, after which the results were disclosed. If the findings were discrepant, colonoscopy was repeated.
  
  
  RESULTS
  A total of 100 patients were evaluated. Nine air-contrast barium enemas were reported to be inadequate, and the cecum was not intubated at colonoscopy in two patients. In the remaining patients, 5 cancers were identified (1 each cecum, transverse colon, descending colon, sigmoid colon, and rectum) by both studies. Sixty-six polypoid lesions were identified in 30 patients. Diverticula were identified in 42 patients by air-contrast barium enema and in 18 patients by colonoscopy. Air-contrast barium enema detected 3 of 36 polypoid lesions 5 mm or less in diameter, 5 of 15 adenomas 6 to 9 mm in size, and 4 of 15 adenomas 10 mm or greater in diameter (sensitivity 8%, 33%, and 27%, respectively). After excluding patients with diverticula, air-contrast barium enema detected 3 of 7 adenomas 10 mm or greater in size. Overall, 12 polypoid lesions or filling defects were identified by air-contrast barium enema that could not be verified by colonoscopy. The specificity of air-contrast barium enema for lesions 1.0 cm or greater in size was 100%; for those 6 mm or greater, it was 97%.
  
  
  CONCLUSIONS
  Air-contrast barium enema accurately detects colon cancer and diverticula. Its sensitivity for detection of polypoid lesions or adenomas is poor and was confounded by the presence of diverticula.
authors.affiliation: Liver Center, Duke University Medical Center, Sands Building Room 334, Research Drive, Durham, NC 27710, USA.
authors.forename: Don C
authors.initials: DC
authors.lastname: Rockey
authors.forename: Johannes
authors.initials: J
authors.lastname: Koch
authors.forename: Judy
authors.initials: J
authors.lastname: Yee
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: McQuaid
authors.forename: Robert A
authors.initials: RA
authors.lastname: Halvorsen
mesh_terms: D018256:Adenomatous Polyps / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D001466:Barium Sulfate; D015331:Cohort Studies; D003092:Colitis / Q000175:diagnosis; D003111:Colonic Polyps / Q000175:diagnosis*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D003287:Contrast Media; D003937:Diagnosis, Differential; D004108:Dilatation, Pathologic / Q000175:diagnosis; D043963:Diverticulosis, Colonic / Q000175:diagnosis*; D004733:Enema; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009780:Occult Blood; D010865:Pilot Projects; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D001466:Barium Sulfate