title: Defecographic study of rectal evacuation in constipated patients and control subjects.
abstract: OBJECTIVE
  To validate a computer-based area calculation method of quantification of rectal evacuation by using defecography videotapes and to use that method to compare evacuation in constipated patients with that in control subjects.
  
  
  METHODS
  For validation of the method, simultaneous defecography and weight measurements were compared in 36 patients with constipation or incontinence. Evacuation was calculated as the rate of change of the contrast medium-covered rectal area (percentage per second) or of the evacuated amount of contrast medium (percentage per second [relative] and grams per second [absolute]). After method validation, from a series of 215 consecutive constipated patients, individuals with an isolated radiologic diagnosis of intussusception greater than 0.6 cm (n = 27), rectocele greater than 2 cm (n = 19), enterocele (n = 12), or paradoxic puborectal muscle contraction (n = 12) were selected. Rectal evacuation in these groups was compared with that in 30 control subjects.
  
  
  RESULTS
  Rectal evacuation rates measured at defecography correlated well with weighed amounts of evacuated contrast medium during the initial and total evacuation periods in 21 patients without contrast medium leak (r = 0.92, P < .001). Constipation overall, a rectocele greater than 2 cm, or paradoxic puborectal muscle contraction were associated with impaired evacuation (P < .001).
  
  
  CONCLUSIONS
  Area calculations of rectal evacuation reflect rectal emptying. A rectocele greater than 2 cm or a paradoxic puborectal muscle contraction may be associated with obstructed defecation.
authors.affiliation: Department of Surgery, Akademiska sjukhuset, Uppsala, Sweden.
authors.forename: U
authors.initials: U
authors.lastname: Karlbom
authors.forename: S
authors.initials: S
authors.lastname: Nilsson
authors.forename: L
authors.initials: L
authors.lastname: Påhlman
authors.forename: W
authors.initials: W
authors.lastname: Graf
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003248:Constipation / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003287:Contrast Media; D003672:Defecation; D019841:Defecography; D005242:Fecal Incontinence / Q000000981:diagnostic imaging / Q000503:physiopathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D020047:Rectocele / Q000000981:diagnostic imaging / Q000503:physiopathology; D012007:Rectum / Q000000981:diagnostic imaging*
chemical_list: D003287:Contrast Media