title: Magnetic resonance enterography has good inter-rater agreement and diagnostic accuracy for detecting inflammation in pediatric Crohn disease.
abstract: BACKGROUND
  Magnetic resonance enterography (MRE) is increasingly relied upon for noninvasive assessment of intestinal inflammation in Crohn disease. However very few studies have examined the diagnostic accuracy of individual MRE signs in children.
  
  
  OBJECTIVE
  We have created an MR-based multi-item measure of intestinal inflammation in children with Crohn disease - the Pediatric Inflammatory Crohn's MRE Index (PICMI). To inform item selection for this instrument, we explored the inter-rater agreement and diagnostic accuracy of individual MRE signs of inflammation in pediatric Crohn disease and compared our findings with the reference standards of the weighted Pediatric Crohn's Disease Activity Index (wPCDAI) and C-reactive protein (CRP).
  
  
  METHODS
  In this cross-sectional single-center study, MRE studies in 48 children with diagnosed Crohn disease (66% male, median age 15.5 years) were reviewed by two independent radiologists for the presence of 15 MRE signs of inflammation. Using kappa statistics we explored inter-rater agreement for each MRE sign across 10 anatomical segments of the gastrointestinal tract. We correlated MRE signs with the reference standards using correlation coefficients. Radiologists measured the length of inflamed bowel in each segment of the gastrointestinal tract. In each segment, MRE signs were scored as either binary (0-absent, 1-present), or ordinal (0-absent, 1-mild, 2-marked). These segmental scores were weighted by the length of involved bowel and were summed to produce a weighted score per patient for each MRE sign. Using a combination of wPCDAI≥12.5 and CRP≥5 to define active inflammation, we calculated area under the receiver operating characteristic curve (AUC) for each weighted MRE sign.
  
  
  RESULTS
  Bowel wall enhancement, wall T2 hyperintensity, wall thickening and wall diffusion-weighted imaging (DWI) hyperintensity were most commonly identified. Inter-rater agreement was best for decreased motility and wall DWI hyperintensity (kappa≥0.64). Correlation between MRE signs and wPCDAI was higher than with CRP. AUC was highest (≥0.75) for ulcers, wall enhancement, wall thickening, wall T2 hyperintensity and wall DWI hyperintensity.
  
  
  CONCLUSIONS
  Some MRE signs had good inter-rater agreement and AUC for detection of inflammation in children with Crohn disease.
authors.affiliation: Division of Gastroenterology, Hepatology & Nutrition, The Hospital for Sick Children, Department of Pediatrics, University of Toronto, 555 University Ave., Toronto, ON, Canada, M5G 1X8. peterchurch@gmail.com.|Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON, Canada. peterchurch@gmail.com.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Church
authors.affiliation: Department of Diagnostic Imaging, The Hospital for Sick Children, Department of Medical Imaging, University of Toronto, Toronto, ON, Canada.
authors.forename: Mary-Louise C
authors.initials: MC
authors.lastname: Greer
authors.affiliation: Department of Diagnostic Imaging, The Hospital for Sick Children, Department of Medical Imaging, University of Toronto, Toronto, ON, Canada.
authors.forename: Ruth
authors.initials: R
authors.lastname: Cytter-Kuint
authors.affiliation: Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON, Canada.|Department of Diagnostic Imaging, The Hospital for Sick Children, Department of Medical Imaging, University of Toronto, Toronto, ON, Canada.
authors.forename: Andrea S
authors.initials: AS
authors.lastname: Doria
authors.affiliation: Division of Gastroenterology, Hepatology & Nutrition, The Hospital for Sick Children, Department of Pediatrics, University of Toronto, 555 University Ave., Toronto, ON, Canada, M5G 1X8.|SickKids Inflammatory Bowel Disease Center, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Anne M
authors.initials: AM
authors.lastname: Griffiths
authors.affiliation: Shaare Zedek Medical Center, Jerusalem, Israel.
authors.forename: Dan
authors.initials: D
authors.lastname: Turner
authors.affiliation: Division of Gastroenterology, Hepatology & Nutrition, The Hospital for Sick Children, Department of Pediatrics, University of Toronto, 555 University Ave., Toronto, ON, Canada, M5G 1X8.|SickKids Inflammatory Bowel Disease Center, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Walters
authors.affiliation: Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON, Canada.|Division of Rheumatology, The Hospital for Sick Children, Department of Pediatrics, University of Toronto, Toronto, ON, Canada.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Feldman
mesh_terms: D000293:Adolescent; D003424:Crohn Disease / Q000150:complications / Q000000981:diagnostic imaging*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007249:Inflammation / Q000150:complications / Q000000981:diagnostic imaging*; D007422:Intestines / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015588:Observer Variation; D015203:Reproducibility of Results; D012189:Retrospective Studies
keywords: Children; Crohn disease; Diagnostic accuracy; Inflammation; Magnetic resonance enterography; Magnetic resonance imaging