title: CT colonography: positioning order and intracolonic pressure.
abstract: OBJECTIVE
  The purpose of this study was to prospectively evaluate the effect of the order of positions on sustained rectal pressure and factors affecting pain perceived by patients during air-insufflated CT colonography.
  
  
  METHODS
  Rectal pressure was measured in the supine and prone positions for CT colonography of 379 patients in two groups. One hundred seventy-seven patients underwent imaging supine and then prone, and 202 patients were prone and then supine. Insufflation and patient pain parameters were based on patient self-report and investigator visualization of observable indicators. Colonic distention, residual feces or fluid, and diverticulosis were evaluated with a semiquantitative scoring system. Fisher's exact, Student's t, and chi-square tests as well as multivariate logistic regression analysis were performed.
  
  
  RESULTS
  Pressure was higher in the prone than in the supine position in both groups (p < 0.001). The measured pressure in the initial position did not differ between groups (p = 0.88). Pressure increased from 38.3 to 40.07 mm Hg in the second position in the supine-first group and decreased from 38.3 to 32.25 mm Hg in the second position in the prone-first group (p < 0.001). The percentage of patients with pain in the second position was 40% in the supine-first group compared with 18% in the prone-first group (p < 0.003). Distention did not differ between the groups. Pain was associated with increased pressure and diverticulosis (p < 0.001) but not with retained feces or fluid.
  
  
  CONCLUSIONS
  Sustained pressure in the air-insufflated colon was higher in the prone than in the supine position. Imaging in the prone position first results in a significant decrease in pressure in the latter phase and less pain. Pain was associated with pressure and diverticulosis.
authors.affiliation: Department of Radiology, Hadassah-Hebrew University Medical Center, Ein Kerem POB 12000, Jerusalem, Israel 91120.
authors.forename: Jacob
authors.initials: J
authors.lastname: Sosna
authors.forename: Jacob
authors.initials: J
authors.lastname: Bar-Ziv
authors.forename: Eugene
authors.initials: E
authors.lastname: Libson
authors.forename: Merab
authors.initials: M
authors.lastname: Eligulashvili
authors.forename: Arye
authors.initials: A
authors.lastname: Blachar
mesh_terms: D015746:Abdominal Pain / Q000000981:diagnostic imaging; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D003106:Colon / Q000502:physiology; D023881:Colonography, Computed Tomographic / Q000379:methods*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007327:Insufflation / Q000379:methods; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011312:Pressure; D016684:Prone Position / Q000502:physiology*; D011446:Prospective Studies; D012007:Rectum / Q000502:physiology; D016683:Supine Position / Q000502:physiology*