title: Iohexol versus diatrizoate for fecal/fluid tagging during CT colonography performed with cathartic preparation: comparison of examination quality.
abstract: OBJECTIVE
  We aimed to compare iohexol vs. diatrizoate as fecal/fluid tagging agents for computed tomography colonography (CTC) regarding examination quality.
  
  
  METHODS
  Forty prospective patients (M:F = 23:17; 63 ± 11.6 years) received CTC using 50 mL (350 mgI/mL) oral iohexol for tagging. Forty other indication-matched, age-matched, and sex-matched patients who underwent CTC using 100 mL diatrizoate for tagging and otherwise the same technique, were retrospectively identified. Two groups were compared regarding overall examination quality, per-patient and per-segment scores of colonic bubbles (0 [no bubbles] to 5 [the largest amount]), and the volume, attenuation, and homogeneity (untagged, layered, and homogeneous) of the residual colonic fluid.
  
  
  RESULTS
  The iohexol group demonstrated a greater amount of colonic bubbles than the diatrizoate group: mean per-patient scores ± SD of 1.2 ± 0.8 vs. 0.7 ± 0.6, respectively (p = 0.003); and rates of segments showing ≥ grade 3 bubbles of 12.9 % (85/659) vs. 1.6 % (11/695), respectively (p = 0.001). Residual colonic fluid amount standardized to the colonic volume did not significantly differ: 7.2 % ± 4.2 vs. 7.8 % ± 3.7, respectively (p = 0.544). Tagged fluid attenuation was mostly comparable between groups and the fluid was homogeneously tagged in 98.7 % (224/227) vs. 99.5 % (218/219) segments, respectively (p = 0.344). Iohexol caused more colonic bubbles when used during cathartic CTC. Otherwise, examination quality was similarly adequate with both iohexol and diatrizoate.
  
  
  CONCLUSIONS
  • When used for tagging, iohexol caused significantly more colonic bubbles than diatrizoate. • The residual colonic fluid amount did not significantly differ between iohexol and diatrizoate. • The quality of fluid tagging was similarly adequate in both iohexol and diatrizoate.
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 138-736, Korea.
authors.forename: Bohyun
authors.initials: B
authors.lastname: Kim
authors.forename: Seong Ho
authors.initials: SH
authors.lastname: Park
authors.forename: Gil-Sun
authors.initials: GS
authors.lastname: Hong
authors.forename: Ju Hee
authors.initials: JH
authors.lastname: Lee
authors.forename: Jong Seok
authors.initials: JS
authors.lastname: Lee
authors.forename: Hyun Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: Ah Young
authors.initials: AY
authors.lastname: Kim
authors.forename: Hyun Kwon
authors.initials: HK
authors.lastname: Ha
mesh_terms: D001826:Body Fluids / Q000000981:diagnostic imaging; D002400:Cathartics / Q000008:administration & dosage*; D003106:Colon / Q000000981:diagnostic imaging; D023881:Colonography, Computed Tomographic / Q000379:methods*; D003287:Contrast Media; D003973:Diatrizoate; D005243:Feces; D005260:Female; D006801:Humans; D007472:Iohexol; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012189:Retrospective Studies
chemical_list: D002400:Cathartics; D003287:Contrast Media; D003973:Diatrizoate; D007472:Iohexol