title: The effects of hypotonic and isotonic negative contrast agent on gastrointestinal distention and physiological intake of 18F-FDG.
abstract: OBJECTIVE
  The objective of this study was to explore the effects of hypotonic and isotonic oral mannitol on intestinal distention and fluorine-18 fluorodeoxyglucose ((18)F-FDG) intake in PET/computed tomography (CT) imaging.
  
  
  METHODS
  A total of 124 patients without gastrointestinal disease were evaluated with PET/CT imaging and divided into four groups using a random number table. Group 1 drank plain water, group 2 drank 2.5% mannitol, group 3 drank 2.5% mannitol and also received 10 mg of scopolamine butylbromide, and group 4 drank 2.5% mannitol and also received 20 mg of scopolamine butylbromide. The patients in each group underwent PET/CT imaging 50 min after (18)F-FDG injection. In these groups, differences such as age, sex, disease distribution, oral liquid amount, and adverse reactions were compared. Gastrointestinal distention and F-FDG intake were analyzed by two experts in nuclear medicine by visual observation. Data were statistically analyzed using a rank-sum test, R×C contingency table, one-way analysis of variance, and a paired t-test.
  
  
  RESULTS
  There were no significant differences in blood glucose levels after oral administration of 2.5% mannitol (t=0.62, P>0.05). Gastrointestinal distention of patients in groups 2, 3, and 4 was superior to that of patients in group 1 (P<0.05/6). In addition to the sigmoid colon and rectum, (18)F-FDG intake in each part of the gastrointestinal tract in groups 2, 3, and 4 was less than that in group 1 (P<0.05/6). Patients in group 4 experienced significantly more adverse reactions compared with patients in the other groups (P<0.05).
  
  
  CONCLUSIONS
  Oral negative contrast agent and hypotonic bowel preparation decreased the physiological intake of (18)F-FDG, increased the distention of the gastrointestinal tract, and thus improved the image quality.
authors.affiliation: Department of Radiology, Southwest Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
authors.forename: Ming-long
authors.initials: ML
authors.lastname: Liang
authors.forename: Yong-ke
authors.initials: YK
authors.lastname: Zhang
authors.forename: San-san
authors.initials: SS
authors.lastname: Hu
authors.forename: Lin
authors.initials: L
authors.lastname: Chen
authors.forename: Hai-tao
authors.initials: HT
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
mesh_terms: D000284:Administration, Oral; D001692:Biological Transport / Q000187:drug effects; D003287:Contrast Media / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism*; D041981:Gastrointestinal Tract / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D007038:Hypotonic Solutions; D007552:Isotonic Solutions; D008297:Male; D008353:Mannitol / Q000008:administration & dosage / Q000494:pharmacology; D008875:Middle Aged; D049268:Positron-Emission Tomography; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D007038:Hypotonic Solutions; D007552:Isotonic Solutions; D019788:Fluorodeoxyglucose F18; D008353:Mannitol