title: High positive predictive value of CT colonography in a referral centre.
abstract: OBJECTIVE
  To assess the positive predictive value (PPV) of CTC in the clinical routine of a dedicated referral centre.
  
  
  METHODS
  All consecutive patients referred for CTC between May 2009 and May 2010 were considered for inclusion in this study. All the patients who, following the diagnosis of a>6 mm polyp or mass at CTC, underwent a post-CTC colonoscopy within eight weeks from diagnosis were included. Per patient PPV for lesions, adenomas and advanced neoplasia was calculated. Chi-square test was used for statistical comparison, and a p value<0.05 was considered to be statistically significant.
  
  
  RESULTS
  516 patients were included in the study. Of them, 76 (14%) patients had at least one lesion≥6 mm on CTC. Overall, 59 (11%) patients were diagnosed at CTC with at least one polyp, 12 (2%) with a flat lesions, and 5 (1%) with a mass. Per-patient PPVs for any lesion>6 mm, neoplasia, and advanced neoplasia were 96% (95% CI: 92-100%), 68.4% (95% CI: 58-79%), and 30% (95% CI: 20-41%), respectively. PPV for neoplasia and advanced neoplasia was substantially higher for >10 mm lesions.
  
  
  CONCLUSIONS
  In dedicated centers, CTC appears to be a highly specific procedure, characterized by a very low rate of false-positive results for >6 mm lesions.
authors.affiliation: Department of Radiological Sciences, Sapienza University of Rome, and Gastroenterology Unit, Nuovo Regina Margherita Hospital, Rome, Italy. francoiafrate@tin.it
authors.forename: F
authors.initials: F
authors.lastname: Iafrate
authors.forename: C
authors.initials: C
authors.lastname: Hassan
authors.forename: M
authors.initials: M
authors.lastname: Ciolina
authors.forename: A
authors.initials: A
authors.lastname: Lamazza
authors.forename: P
authors.initials: P
authors.lastname: Baldassari
authors.forename: A
authors.initials: A
authors.lastname: Pichi
authors.forename: A
authors.initials: A
authors.lastname: Zullo
authors.forename: A
authors.initials: A
authors.lastname: Stagnitti
authors.forename: M
authors.initials: M
authors.lastname: Iannitti
authors.forename: M
authors.initials: M
authors.lastname: Rengo
authors.forename: A
authors.initials: A
authors.lastname: Laghi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003111:Colonic Polyps / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D023881:Colonography, Computed Tomographic / Q000706:statistics & numerical data*; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D015897:Comorbidity; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012017:Referral and Consultation / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity