title: In patients with slow transit constipation, the pattern of colonic transit delay does not differentiate between those with and without impaired rectal evacuation.
abstract: BACKGROUND
  Severe constipation may be subclassified on the basis of speed of colonic transit and efficacy of rectal evacuation. It is hypothesized that rectal evacuatory disorder (RED) may be associated with a secondary transit delay.
  
  
  OBJECTIVE
  To determine whether scintigraphy can discriminate between slow transit constipation (STC) with or without coexistent RED on the basis of progression of isotope throughout the colon and by analyses of specific regions of interest.
  
  
  METHODS
  One hundred ninety-six patients with STC (radio-opaque marker study) were subclassified according to results of proctography into those with a RED (STC-RED N = 30) or normal (STC-ONLY N = 41) evacuation. Patients subsequently underwent colonic scintigraphy. Distribution of generalized or left-sided patterns of colonic transit was assessed. Severities of transit delay and regional transit at specific time points were also evaluated.
  
  
  RESULTS
  Time-activity curves and severity of global transit delay were similar between groups as were the incidences of generalized and left-sided patterns of delay. Percentage of radioisotope retention in the right colon at 18 h was higher for the STC-ONLY group (P < 0.05), but this was poorly discriminative. No differences were observed for the percentage of radioisotope retained in the left colon at later scans.
  
  
  CONCLUSIONS
  Global and regional assessment of colonic transit by scintigraphy failed to discriminate between patients with STC with or without coexistent RED. Thus, RED is not associated with a specific pattern of transit delay and scintigraphy alone cannot predict the presence or absence of RED, knowledge of which is important for management.
authors: Centre for Academic Surgery (GI Physiology Unit), Barts & The London, Queen Mary's School of Medicine and Dentistry, London, UK.
authors: Natalie
authors: N
authors: Zarate
authors: Charlie H
authors: CH
authors: Knowles
authors: Margaret
authors: M
authors: Newell
authors: Neil W
authors: NW
authors: Garvie
authors: Marc A
authors: MA
authors: Gladman
authors: Peter J
authors: PJ
authors: Lunniss
authors: S Mark
authors: SM
authors: Scott
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003248:Constipation / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D005260:Female; D005772:Gastrointestinal Transit; D006801:Humans; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D012002:Rectal Diseases / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D013997:Time Factors