title: Evaluation of simethicone-coated cellulose as a negative oral contrast agent for abdominal CT.
abstract: OBJECTIVE
  Because of the increased clinical use of computed tomography (CT) for imaging the abdominal vasculature and urinary tract, there is a need for negative contrast agents. The authors undertook this study to assess the suitability of simethicone-coated cellulose (SCC), which is approved for use as an oral contrast agent in sonography, for use as a negative oral contrast agent in abdominal CT.
  
  
  METHODS
  This prospective study involved 40 adult patients scheduled to undergo abdominal CT for the evaluation of hematuria. Prior to scanning, 20 subjects received 800 mL of SCC and 20 received 800 mL of water as an oral contrast agent. Imaging was performed with a multi-detector row helical scanner in two phases, according to the abdominal CT protocol used for hematuria evaluation at the authors' institution. The first, "early" phase began an average of 15 minutes after the ingestion of contrast material; the second, "late" phase began an average of 45 minutes after the ingestion of contrast material. Blinded analysis was performed by three abdominal radiologists separately, using a three-point scale (0 = poor, 1 = acceptable, 2 = excellent) to assess the effectiveness of SCC for marking the proximal, middle, and distal small bowel. Average scores for enhancement with SCC and with water were obtained and compared. Statistical analysis was performed with a Wilcoxon signed-rank test.
  
  
  RESULTS
  SCC was assigned higher mean scores than water for enhancement in each segment of the bowel, both on early-phase images (0.8-1.35 for SCC vs 0.6-1.1 for water) and on late-phase images (1.1-1.4 vs 0.81-0.96). Bowel marking with SCC, particularly in the jejunum and ileum, also was rated better than that with water in a high percentage of patients. The differences between the scores for water and for SCC, however, were not statistically significant (P > .05).
  
  
  CONCLUSIONS
  SCC is effective as a negative oral contrast agent for small bowel marking at CT.
authors.affiliation: Department of Radiology, Division of Abdominal Imaging and Intervention, Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, Boston, MA 02114, USA.
authors.forename: Dushyant V
authors.initials: DV
authors.lastname: Sahani
authors.forename: Kartik S
authors.initials: KS
authors.lastname: Jhaveri
authors.forename: Roy V
authors.initials: RV
authors.lastname: D'souza
authors.forename: Jose C
authors.initials: JC
authors.lastname: Varghese
authors.forename: Elkan
authors.initials: E
authors.lastname: Halpern
authors.forename: Mukesh G
authors.initials: MG
authors.lastname: Harisinghani
authors.forename: Peter F
authors.initials: PF
authors.lastname: Hahn
authors.forename: Sanjay
authors.initials: S
authors.lastname: Saini
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D002482:Cellulose / Q000008:administration & dosage; D003287:Contrast Media / Q000008:administration & dosage*; D004064:Digestive System / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012841:Simethicone / Q000008:administration & dosage; D036542:Tomography, Spiral Computed
chemical_list: D003287:Contrast Media; C120539:SonoRx; D012841:Simethicone; D002482:Cellulose