title: Laxative-free CT colonography.
abstract: OBJECTIVE
  The aim of this study was to determine if the introduction of faecal tagging to CT colonography (CTC) made the examination easier to tolerate or reduced the number of false-positives.
  
  
  METHODS
  Our department changed bowel preparation for CT colonography from Picolax (Ferring Pharmaceuticals Ltd, London, UK) to Gastrografin (Bracco Diagnostics Inc, Princeton, NJ) only with a modified diet. Questionnaires were given to a subgroup of patients within these cohorts. The numbers of false-positives were compared between two cohorts before and after this change. false-positives were defined as lesions reported on CT that were not confirmed by subsequent endoscopic examination. Polyps were matched if they were in the same or adjacent segments, and were within 5 mm of the reported size.
  
  
  RESULTS
  412 patients were identified from the Picolax cohort, and 116 from the Gastrografin cohort. 62 patients in each group completed questionnaires. Gastrografin produced less diarrhoea; 34% had five or more bowel motions in the previous day and night, compared with 77% for Picolax (p<0.001), although more patients found drinking it unpleasant compared with Picolax (85% reported drinking Picolax as "easy" vs 61% for Gastrografin; p=0.002). Picolax produced more non-diagnostic examinations, although this difference was not statistically significant. There was not a significant reduction in the numbers of false-positives (2 out of 112 for Gastrografin group, 14 out of 389 for the Picolax group; p=0.54).
  
  
  CONCLUSIONS
  Switching from Picolax to Gastrografin as a CTC preparation technique produced less diarrhoea, but did not reduce the number of false-positives.
authors.affiliation: Department of Radiology, John Radcliffe Hospital, Oxford, UK. andrewslater99@hotmail.com
authors.forename: A
authors.initials: A
authors.lastname: Slater
authors.forename: M
authors.initials: M
authors.lastname: Betts
authors.forename: H
authors.initials: H
authors.lastname: D'Costa
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002400:Cathartics / Q000008:administration & dosage* / Q000009:adverse effects; D002951:Citrates; D003111:Colonic Polyps / Q000000981:diagnostic imaging*; D023881:Colonography, Computed Tomographic / Q000379:methods*; D003287:Contrast Media / Q000008:administration & dosage* / Q000009:adverse effects; D003967:Diarrhea / Q000139:chemically induced; D003974:Diatrizoate Meglumine / Q000008:administration & dosage* / Q000009:adverse effects; D057915:Drug Substitution; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009942:Organometallic Compounds; D017060:Patient Satisfaction; D010847:Picolines / Q000008:administration & dosage* / Q000009:adverse effects; D011795:Surveys and Questionnaires
chemical_list: D002400:Cathartics; D002951:Citrates; D003287:Contrast Media; D009942:Organometallic Compounds; D010847:Picolines; D003974:Diatrizoate Meglumine; C005701:picosulfate sodium