title: Small bowel strictures in Crohn's disease: a quantitative investigation of intestinal motility using MR enterography.
abstract: BACKGROUND
  Intestinal stricturing and aberrant small bowel motility are common complications in patients with Crohn's disease (CD) leading to significant morbidity. A retrospective study was performed quantifying small bowel motility within and upstream of strictures in CD patients using magnetic resonance enterography (MRE).
  
  
  METHODS
  A total of 91 subjects with stricturing CD (mean age 36 range 18-88) and undergoing MRE with dynamic motility imaging were identified. Of this cohort, 84 subjects were scanned at 1.5 T field strength with the remainder at 3 T. Linear regions of interest (ROI) were placed at the stricture, immediately upstream of the stricture, and in a proximal normal segment of bowel. Maximum bowel calibre (mm) and motility (Arbitrary units) at each ROI were calculated using previously validated software. Diameters and motility were compared using repeat measures anova and diameter correlated with motility score. In 21 subjects with follow-up MRE, ROIs were duplicated and percentage diameter and motility change across the two time points correlated.
  
  
  RESULTS
  Mean diameter within the normal, prestricture and strictured bowel was 20, 30, and 15 mm (p < 0.001) with motility score 0.43, 0.28, and 0.15 AU, respectively (p < 0.001). There was a negative correlation between prestricture bowel diameter and motility (Pearson's R = -0.47, p < 0.001). For patients with follow-up MRE, there was a negative correlation between percentage change in prestricture diameter and motility, Spearman's Rho -0.6 p = 0.007.
  
  
  CONCLUSIONS
  Quantified small bowel motility during MRE differs significantly between normal, prestricture, and strictured bowel. As prestricture bowel dilates, motility decreases, although this appears reversible in some.
authors.affiliation: Centre for Medical Imaging, UCL, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Menys
authors.forename: E
authors.initials: E
authors.lastname: Helbren
authors.forename: J
authors.initials: J
authors.lastname: Makanyanga
authors.forename: A
authors.initials: A
authors.lastname: Emmanuel
authors.forename: A
authors.initials: A
authors.lastname: Forbes
authors.forename: A
authors.initials: A
authors.lastname: Windsor
authors.forename: S
authors.initials: S
authors.lastname: Punwani
authors.forename: S
authors.initials: S
authors.lastname: Halligan
authors.forename: D
authors.initials: D
authors.lastname: Atkinson
authors.forename: S A
authors.initials: SA
authors.lastname: Taylor
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003424:Crohn Disease / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D005769:Gastrointestinal Motility; D006801:Humans; D007415:Intestinal Obstruction / Q000503:physiopathology*; D007421:Intestine, Small / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D055815:Young Adult
keywords: MR enterography; motility; small bowel