CT colonography without cathartic preparation: positive predictive value and patient experience in clinical practice
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To determine the positive predictive value (PPV) for polyps ≥6 mm detected at CT colonography (CTC) performed without cathartic preparation, with low-dose iodine faecal tagging regimen and to evaluate patient experience.
1920 average-risk patients underwent CTC without cathartic preparation. Faecal tagging was performed by diatrizoate meglumine and diatrizoate sodium at a total dose of 60 ml (22.2 g of iodine).The standard interpretation method was primary 3D with 2D problem solving. We calculated per-patient and per-polyp PPV in relation to size and morphology. All colonic segments were evaluated for image quality (faecal tagging, amount of liquid and solid residual faeces and luminal distension). Patients completed a questionnaire before and after CTC to assess preparation and examination experience.
Per-polyp PPV for detected lesions of ≥6 mm, 6–9 mm, ≥10 mm and ≥30 mm were 94.3%, 93.1%, 94.7% and 98%, respectively. Per-polyp PPV, according to lesion morphology, was 94.6%, 97.3% and 85.1% for sessile, pedunculated and flat polyps, respectively. Per-patient PPV was 92.8%. Preparation without frank cathartics was reported to cause minimal discomfort by 78.9% of patients.
CTC without cathartic preparation and low-dose iodine faecal tagging may yield high PPVs for lesions ≥6 mm and is well accepted by patients.
• Computed tomographic colonography (CTC) without cathartic preparation is well accepted by patients
• Cathartic-free faecal tagging CTC yields high positive predictive values
• CTC without cathartic preparation could improve uptake of colorectal cancer screening
KeywordsCT-colonography Faecal tagging Patient acceptance Colorectal cancer Bowel preparation colorectal polyp Adenoma
We thank C. P. Cadórniga for critical review of this manuscript and A. Salgado for his help with the data analysis.
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