title: Comparative evaluation of the fecal-tagging quality in CT colonography: barium vs. iodinated oral contrast agent.
abstract: OBJECTIVE
  The purpose of this evaluation was to compare the tagging quality of a barium-based regimen with that of iodine-based regimens for computed tomographic (CT) colonography.
  
  
  METHODS
  Tagging quality was assessed retrospectively in three different types of fecal-tagging CT colonographic cases: 24 barium-based cases, 22 nonionic iodine-based cases, and 24 ionic iodine-based cases. For the purpose of evaluation, the large intestine was divided into six segments, and the tagging homogeneity of a total of 420 segments (70 patients) was graded by three blinded readers from 0 (heterogeneous) to 4 (homogeneous).
  
  
  RESULTS
  For barium-based cases, the average score for the three readers was 2.4, whereas it was 3.4 for nonionic iodine and 3.6 for ionic iodine. The percentages of segments that were assigned scores of 4 (excellent tagging [100%]) were 11.6%, 61.9%, and 72.9% for the barium-based, nonionic iodine-based, and ionic iodine-based regimens, respectively. The homogeneity scores of iodine-based fecal-tagging regimens were significantly higher than those of the barium-based fecal-tagging regimen (P < .001). The CT attenuation values of tagging in the cases were also assessed: the minimum and maximum values were significantly higher for the iodine-based regimens than for the barium-based regimen (P < .001).
  
  
  CONCLUSIONS
  The iodine-based fecal-tagging regimens provide significantly greater homogeneity in oral-tagging fecal material than the barium-based fecal-tagging regimen. Iodine-based fecal-tagging regimens can provide an appropriate method for use in nonlaxative or minimum-laxative CT colonography.
authors: 3D Imaging Laboratory, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 25 New Chardon Street, Suite 400C, Boston, MA 02114, USA. nagata7@aol.com
authors: Koichi
authors: K
authors: Nagata
authors: Anand Kumar
authors: AK
authors: Singh
authors: Minal Jagtiani
authors: MJ
authors: Sangwaiya
authors: Janne
authors: J
authors: Näppi
authors: Michael E
authors: ME
authors: Zalis
authors: Wenli
authors: W
authors: Cai
authors: Hiroyuki
authors: H
authors: Yoshida
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001466:Barium Sulfate / Q000008:administration & dosage; D003106:Colon / Q000000981:diagnostic imaging*; D023881:Colonography, Computed Tomographic / Q000379:methods*; D003287:Contrast Media / Q000008:administration & dosage; D003974:Diatrizoate Meglumine / Q000008:administration & dosage; D005243:Feces; D005260:Female; D006801:Humans; D007472:Iohexol / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D011856:Radiographic Image Enhancement / Q000379:methods; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016037:Single-Blind Method
chemical_list: D003287:Contrast Media; D001466:Barium Sulfate; D003974:Diatrizoate Meglumine; D007472:Iohexol