CT colonography after incomplete colonoscopy in subjects with positive faecal occult blood test

Abstract

surgery for colonic masses of indeterminate nature. Four subjects refused further examinations. CTC correctly identified 2 colonic masses and 20 polyps. PPV for masses or polyps greater than 9 mm was of 87.5%. Per-lesion and per-segment PPV were, respectively, 83.3% and 83.3% for polyps greater or equal to 10 mm, and 77.8% and 85.7% for polyps of 6-9 mm. CONCLUSION: In the context of a screening program for CRC based on FOBT, CTC shows high per-segment and per-lesion PPV for colonic masses and polyps greater than 9 mm. Therefore, CTC has the potential to become a useful technique for evaluation of the non visualized part of the colon after incomplete colonoscopy.

Alternatives to Incomplete Colonoscopy

“…In another study by Sali et al, 42 patients with a positive fecal occult blood test (FOBT) underwent CTC after failed initial screening colonoscopy; 50 % of these showed polyps or masses for which repeat colonoscopy was performed. CTC had a PPV of 87.5 % for polyps ≥9 mm [54].…”

Frequency and efficacy of additional investigations following incomplete colonoscopies: A population-based analysis

“…Since 2011, CT colonography with gas has been used increasingly (41.7%) with reference to the published guidelines for incomplete colonoscopy [38,39]. Following incomplete colonoscopy in subjects with positive FOBT, CT colonography has been shown to demonstrate high per-segment and per-lesion positive predictive values for colonic masses and polyps greater than 9 mm [40]. Despite the low rate (2.4%) of neoplasia detected by secondary colonic evaluation in the present study, the detection of a late-stage cancer by surveillance colonoscopy in 3 patients who did not undergo a secondary examination highlights the usefulness of completing a colonic evaluation shortly after incomplete colonoscopy, particularly in those with an occlusive cancer in the distal colon.…”

CT colonography with rectal iodine tagging: Feasibility and comparison with oral tagging in a colorectal cancer screening population

“…Image quality (fluid or stool), thus improving the quality of interpretation in terms of both sensitivity and specificity and reducing the number of false positives [1,2]. Usually, fecal tagging can be achieved with oral administration of either iodinated contrast media or barium or both; this way, only residual stool and fluid will be marked by contrast medium, whereas bowel wall and colonic lesions will not [6,22,23].…”

“…CT colonography (CTC) has gained wide reliability in the clinical practice and nowadays is a standardized radiological procedure for the evaluation of colonic lesions that has superseded double contrast barium enema owing to its higher diagnostic accuracy, better patient tolerance, and lower radiation dose [1,2]. Patient's compliance, the safety of the CTC procedure, and the diagnostic accuracy of CTC depend on multiple factors (e.g.…”