title: Is intravenous contrast necessary for detection of clinically significant extracolonic findings in patients undergoing CT colonography?
abstract: OBJECTIVE
  To determine whether intravenous contrast (IVC) is necessary for detection of extracolonic findings (ECFs) in patients undergoing CT colonography (CTC).
  
  
  METHODS
  We performed a retrospective review of CT findings in 179 cases of CTC studies performed over 18 months where both pre-contrast (NECT) and post-contrast (CECT) scans were performed in the prone and supine positions, respectively, in the same patients. All ECFs were recorded on a per patient basis and graded according to the colonography reporting and data system classification.
  
  
  RESULTS
  There was no significant change in E grade for the cohort (p = 0.171) between the NECT and CECT scans. On the CECT scans, additional findings were detected in 49.1% of patients. Overall, there were 27/179 (15.1%) patients graded E3 and 18/179 (10.1%) patients graded E4 on the CECT study. Compared with the NECT study, there was a decrease of 12.9% of patients graded E3 and no change in the number of patients graded E4.
  
  
  CONCLUSIONS
  With IVC administration, additional ECFs are detected in nearly half of all patients. However, there was no increase in the number of patients with clinically significant lesions. The risk-benefit ratio of routine IVC administration for CTC in symptomatic patients thus requires further evaluation.
  
  
  CONCLUSIONS
  This study reviews the utility of IVC in CTC and is thus relevant to current clinical practice at many institutions.
authors.affiliation: Department of Diagnostic Radiology, Tan Tock Seng Hospital, Singapore.
authors.forename: T Y
authors.initials: TY
authors.lastname: Yau
authors.forename: Laa
authors.initials: L
authors.lastname: Alkandari
authors.forename: B
authors.initials: B
authors.lastname: Haaland
authors.forename: W
authors.initials: W
authors.lastname: Low
authors.forename: C H
authors.initials: CH
authors.lastname: Tan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D023881:Colonography, Computed Tomographic; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D033162:Incidental Findings; D008297:Male; D008875:Middle Aged; D011856:Radiographic Image Enhancement / Q000379:methods; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media