title: CT colonography without cathartic preparation: positive predictive value and patient experience in clinical practice.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  CTC without cathartic preparation and low-dose iodine faecal tagging may yield high PPVs for lesions ≥ 6 mm and is well accepted by patients.
  
  
  CONCLUSIONS
  • 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.
authors.affiliation: Complexo Hospitalario Universitario de Vigo - CHUVI, c/Pizarro 22, 36204 Vigo, Pontevedra, Spain. carmen.zueco.zueco@sergas.es
authors.forename: Carmen
authors.initials: C
authors.lastname: Zueco Zueco
authors.forename: Carolina
authors.initials: C
authors.lastname: Sobrido Sampedro
authors.forename: Juan D
authors.initials: JD
authors.lastname: Corroto
authors.forename: Paula
authors.initials: P
authors.lastname: Rodriguez Fernández
authors.forename: Manuela
authors.initials: M
authors.lastname: Fontanillo Fontanillo
mesh_terms: D000368:Aged; D002400:Cathartics; D003111:Colonic Polyps / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D023881:Colonography, Computed Tomographic / Q000706:statistics & numerical data*; D003287:Contrast Media; D003974:Diatrizoate Meglumine; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015995:Prevalence; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013030:Spain / Q000453:epidemiology
chemical_list: D002400:Cathartics; D003287:Contrast Media; D003974:Diatrizoate Meglumine