Comparison between CT Colonography and Double-Contrast Barium Enema for Colonic Evaluation in Patients with Renal Insufficiency

OBJECTIVE: To compare the CT colonography (CTC) and double-contrast barium enema (DCBE) for colonic evaluation in patients with renal insufficiency. MATERIALS AND 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. CONCLUSION: 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.