title: Extracolonic findings (ECF) on CT colonography (CTC) in patients presenting with colorectal symptoms.
abstract: BACKGROUND
  Computed tomographic colonography (CTC) is now an established method for imaging the colon and rectum in the screening and symptomatic setting. Additional benefit of CTC is the ability to assess for extracolonic findings especially in patients presenting with colorectal symptoms.
  
  
  OBJECTIVE
  To determine prevalence of extracolonic findings (ECF) in symptomatic patients undergoing CTC and determine accuracy of CTC for exclusion of significant abdominal disease and extracolonic malignancy (ECM).
  
  
  METHODS
  A total of 1359 unenhanced prone and postcontrast supine CTC studies were performed between March 2002 and December 2007. ECF were retrospectively classified according to C-RADS criteria into E1 to E4 findings. For ECM, a gold standard of clinical and/or radiological follow-up supplemented with data from the regional cancer registry with a median follow-up of 42 months was created. Sensitivity and negative predictive values for ECM was calculated.
  
  
  RESULTS
  Following exclusions, 1177 CTCs were analyzed. Of 1423 extracolonic findings reported, 328/1423 (23%) E3 and 100/1423 (7%) E4 (including six eventual FP studies) findings were identified. Thirty-two ECMs were confirmed following further investigations. Seven further small ECMs were detected during the entire follow-up, of which two were potentially visible in retrospect (false-negative studies). Additional tests were generated from 55/1177 (4.7%) studies. Sensitivity and negative predictive value for ECM was 94.1% (95% CI 78.9-98.9%) and 99.8% (95% CI 99.3-99.9%), respectively.
  
  
  CONCLUSIONS
  One in 37 patients were found to have an ECM. Two potentially detectable cancers were missed. Only a small proportion of patients underwent additional work-up.
authors.affiliation: Department of General Surgery.
authors.forename: Sarit
authors.initials: S
authors.lastname: Badiani
authors.forename: Silvia
authors.initials: S
authors.lastname: Tomas-Hernandez
authors.forename: Sharad
authors.initials: S
authors.lastname: Karandikar
authors.forename: Shuvro
authors.initials: S
authors.lastname: Roy-Choudhury
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D023881:Colonography, Computed Tomographic / Q000379:methods*; D003287:Contrast Media; D004067:Digestive System Neoplasms / Q000000981:diagnostic imaging*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D033162:Incidental Findings; D007479:Iopamidol; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D015995:Prevalence; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014565:Urogenital Neoplasms / Q000000981:diagnostic imaging*
chemical_list: D003287:Contrast Media; D007479:Iopamidol
keywords: CT colonography; extracolonic findings; extracolonic malignancy; negative predictive value; sensitivity and specificity; virtual colonoscopy