title: Immediate CT pneumocolon for failed colonoscopy; comparison with routine pneumocolon.
abstract: OBJECTIVE
  To assess the role and reliability of 2D CT pneumocolon in the diagnosis of colonic malignancy, and compare feasibility of referral sources.
  
  
  METHODS
  A prospective study of 50 patients with suspected large bowel malignancy. Patients underwent bowel cleansing, rectal air insufflation and contrast enhanced CT with 5 mm collimation, 3 mm reconstruction and a pitch of 1.4. Subsequent correlation was with pathology (16), colonoscopy (13), barium enema (5), ERCP (1) and clinical follow-up alone (8).
  
  
  RESULTS
  Diagnostic images were obtained in 43/50 patients (86% feasibility). Follow-up was obtained in 35/43 patients (one patient died of an unrelated cause, and seven patients were deemed unfit for further investigation). Seventeen colonic carcinomas were diagnosed (three false-positives: one ischaemic colitis, one diverticular stricture and one faecal mass), one diverticular stricture, one fistula, one pancreatic carcinoma and one ovarian malignancy. The remaining 14 were negative. Overall sensitivity was 100% (for lesions >1.5 cm) with a specificity of 94% for structural abnormalities, but only 82% for the correct identification of malignancy.
  
  
  CONCLUSIONS
  Computed tomography (CT) pneumocolon is a reliable alternative to barium enema where colonoscopy is incomplete, with the advantage of extraluminal screening, and examination of the proximal bowel. In the frail elderly or young unfit patient, it is a valuable additional diagnostic tool.
authors.affiliation: Department of Radiology, Pilgrim Hospital, Sibsey Road, Boston, UK. Ingrid.Britton@ULH.NHS.UK
authors.forename: I
authors.initials: I
authors.lastname: Britton
authors.forename: S
authors.initials: S
authors.lastname: Dover
authors.forename: R
authors.initials: R
authors.lastname: Vallance
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003110:Colonic Neoplasms / Q000000981:diagnostic imaging*; D003113:Colonoscopy; D005189:False Positive Reactions; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011029:Pneumoradiography / Q000379:methods*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*