title: Comparison between CT colonography and double-contrast barium enema for colonic evaluation in patients with renal insufficiency.
abstract: OBJECTIVE
  To compare the CT colonography (CTC) and double-contrast barium enema (DCBE) for colonic evaluation in patients with renal insufficiency.
  
  
  METHODS
  Two sequential groups of consecutive patients with renal insufficiency who had a similar risk for colorectal cancer, were examined by DCBE (n = 182; mean ± SD in age, 51 ± 6.4 years) and CTC (n = 176; 50 ± 6.7 years), respectively. CTC was performed after colon cleansing with 250-mL magnesium citrate (n = 87) or 4-L polyethylene glycol (n = 89) and fecal tagging. DCBE was performed after preparation with 250-mL magnesium citrate. Patients with colonic polyps/masses of ≥ 6 mm were subsequently recommended to undergo a colonoscopy. Diagnostic yield and positive predictive value (PPV) for colonic polyps/masses, examination quality, and examination-related serum electrolyte change were retrospectively compared between the two groups.
  
  
  RESULTS
  Both the CTC and DCBE were positive for colonic polyps/masses in 28 (16%) of 176 and 11 (6%) of 182 patients, respectively (p = 0.004). Among patients with positive findings, 17 CTC and six DCBE patients subsequently underwent a colonoscopy and yielded a PPV of 88% (15 of 17 patients) and 50% (3 of 6 patients), respectively (p = 0.089). Thirteen patients with adenomatous lesions were detected in the CTC group (adenocarcinoma [n = 1], advanced adenoma [n = 6], and non-advanced adenoma [n = 6]), as compared with two patients (each with adenocarcinoma and advanced adenoma) in the DCBE group (p = 0.003). Six (3%) of 176 CTC and 16 (9%) of 182 DCBE examinations deemed to be inadequate (p = 0.046). Electrolyte changes were similar in the two groups.
  
  
  CONCLUSIONS
  In patients with renal insufficiency, CTC has a higher diagnostic yield and a marginally higher PPV for detecting colorectal neoplasia, despite a similar diagnostic yield for adenocarcinoma, and a lower rate of inadequate examinations as compared with DCBE.
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul 138-736, Korea.
authors.forename: Sun-Young
authors.initials: SY
authors.lastname: Chung
authors.forename: Seong Ho
authors.initials: SH
authors.lastname: Park
authors.forename: Seung Soo
authors.initials: SS
authors.lastname: Lee
authors.forename: Ju Hee
authors.initials: JH
authors.lastname: Lee
authors.forename: Ah Young
authors.initials: AY
authors.lastname: Kim
authors.forename: Su-Kil
authors.initials: SK
authors.lastname: Park
authors.forename: Duck Jong
authors.initials: DJ
authors.lastname: Han
authors.forename: Hyun Kwon
authors.initials: HK
authors.lastname: Ha
mesh_terms: D000704:Analysis of Variance; D001466:Barium Sulfate; D003111:Colonic Polyps / Q000175:diagnosis / Q000000981:diagnostic imaging; D023881:Colonography, Computed Tomographic; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging; D003287:Contrast Media; D004733:Enema; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D051437:Renal Insufficiency / Q000150:complications*; D012307:Risk Factors; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D001466:Barium Sulfate