title: Use of geometric center and parametric images in scintigraphic colonic transit studies.
abstract: OBJECTIVE
  Scintigraphic studies give detailed information on colonic transit. In this study, several methods of presenting such data were compared and discussed. The aim of the study was to evaluate the role of geometric center (GC) and parametric images in interpretation of colonic transit studies.
  
  
  METHODS
  Segmental colonic transit was measured in 117 patients: 50 with constipation, 24 with irritable bowel syndrome, 22 with fecal incontinence, 14 who were postsurgery, and 7 normal volunteers. 111In-labeled resin was administered in a pH-sensitive capsule, and images were acquired for 3 days. The percentage of activity in four regions of colon and in the feces was measured.
  
  
  RESULTS
  Five patterns of colonic transit were identified (16 rapid transit, 48 intermediate, 14 generalized delay, 5 left-sided delay, and 34 right-sided delay). The geometric center (sum of fraction of activity x region number) was calculated at each time point. Using the geometric center, the groups could be differentiated (P < 0.01) except for those with left-sided delay. In individual patients, patterns of colonic transit could not be determined using the geometric center alone. Gray-scale presentation of percent activity in each region (parametric images) allowed patterns of colonic transit to be identified in individuals.
  
  
  CONCLUSIONS
  Use of the geometric center is suitable for comparison of groups of patients, whereas parametric images identify patterns in individual patients.
authors.affiliation: Department of Physics and Nuclear Medicine, City Hospital Trust, Birmingham, England.
authors.forename: A
authors.initials: A
authors.lastname: Notghi
authors.forename: R
authors.initials: R
authors.lastname: Hutchinson
authors.forename: D
authors.initials: D
authors.lastname: Kumar
authors.forename: N
authors.initials: N
authors.lastname: Tulley
authors.forename: L K
authors.initials: LK
authors.lastname: Harding
mesh_terms: D000704:Analysis of Variance; D003106:Colon / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005772:Gastrointestinal Transit; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007205:Indium Radioisotopes; D011237:Predictive Value of Tests; D011877:Radionuclide Imaging
chemical_list: D007205:Indium Radioisotopes