title: Double-contrast barium enema: use in practice and implications for CT colonography.
abstract: OBJECTIVE
  This study examines the use and yield of double-contrast barium enemas (DCBEs) for colorectal polyp detection in current clinical practice outside the research setting.
  
  
  METHODS
  My colleagues and I retrospectively reviewed adult DCBE studies performed in routine clinical practice at a single academic institution from 2001 through 2004 by reviewing the official radiology and colonoscopy reports. Data were collected on indications for a DCBE, number of positive and negative DCBE reports, results of a DCBE after failed colonoscopy, and professional profiles of the radiologists who performed the DCBEs. Correlation for colon polyp detection was made by reviewing reports of colonoscopy performed within 12 months before or after a DCBE. Polyp detection and matching analysis used a six-segment colon localization scheme.
  
  
  RESULTS
  A total of 244 out of 665 (36.7%) barium enema studies were performed using the double-contrast technique over the 4-year period-that is, approximately one per week. The most common indication for a DCBE (109/244 or 44.6%) was to complete a failed, incomplete, or inconclusive colonoscopy. Overall, only 14 of the 244 (5.7%) studies gave positive reports for polyps, and of these, five were shown to be false-positive at later colonoscopy. Only six polyps 10 mm or larger were positively detected during the entire study, which is approximately one per 60 studies or one every 8 months. In 104 patients who had negative DCBEs after failed or inconclusive colonoscopy, more than 50 subcentimeter polyps had been detected and removed, yet not one additional polyp was detected by a DCBE. Of the 15 radiologists performing the DCBEs during the study period, 89.7% of the studies were done by four individuals. Three of these four radiologists were older than 60 years at the beginning of the study, and two of them are now either retired or no longer perform fluoroscopy.
  
  
  CONCLUSIONS
  In our center, a DCBE is a low-yield procedure for detecting polyps, with a high false-positive rate, and is not likely to be performed by experienced practitioners in the future.
authors.affiliation: Department of Radiology, Boston Medical Center, Boston University School of Medicine, 88 East Newton, Atrium 2, Boston, MA 02118, USA. joseph.ferrucci@bmc.org
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Ferrucci
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001466:Barium Sulfate; D003111:Colonic Polyps / Q000175:diagnosis / Q000000981:diagnostic imaging*; D023881:Colonography, Computed Tomographic; D003113:Colonoscopy; D003287:Contrast Media / Q000008:administration & dosage*; D004733:Enema; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D001466:Barium Sulfate