title: Non-perforating small bowel Crohn's disease assessed by MRI enterography: derivation and histopathological validation of an MR-based activity index.
abstract: OBJECTIVE
  To develop and validate a qualitative scoring system for enteric Crohn's disease activity using MR enterography (MRE).
  
  
  METHODS
  MRE was performed in 16 patients (mean age 33, 8 male) undergoing small bowel resection. Mural thickness, T2 signal, contrast enhancement, and perimural oedema were scored qualitatively (0-3) at 44 locations. Transmural histopathological scoring of acute inflammation (AIS) was performed at all locations (score 0-13). MRI parameters best predicting AIS were derived using multivariate analysis. The MRI activity index was applied to 26 Crohn's patients (mean age 32, range 13-69 years, 15 male) and correlated to terminal ileal biopsy scores of acute inflammation ("eAIS" score 1-6). Receiver operator characteristic curves were calculated.
  
  
  RESULTS
  Mural thickness (coefficient 1.34 (95% CI 0.36, 2.32)], p=0.007) and T2 signal (coefficient 0.90 (95% CI -0.24, 2.04) p=0.06) best predicted AIS (AIS=1.79+1.34*mural thickness+0.94*mural T2 score [R-squared 0.52]). There was a significant correlation between the MRI index and eAIS (Kendall's tau=0.40, 95% CI 0.11-0.64, p=0.02). The model achieved a sensitivity of 0.81 (95% CI 0.54-0.96), specificity of 0.70 (0.35-0.93) and AUC 0.77 for predicting acute inflammation (eAIS ≥2).
  
  
  CONCLUSIONS
  A simple qualitative MRI Crohn's disease activity score appears predictive against a histopathological standard of reference.
authors.affiliation: Department of Specialist Imaging, University College Hospital London, 235 Euston Road, London NW1 2BU, United Kingdom. mikejsteward@gmail.com
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Steward
authors.forename: Shonit
authors.initials: S
authors.lastname: Punwani
authors.forename: Ian
authors.initials: I
authors.lastname: Proctor
authors.forename: Yvette
authors.initials: Y
authors.lastname: Adjei-Gyamfi
authors.forename: Fiona
authors.initials: F
authors.lastname: Chatterjee
authors.forename: Stuart
authors.initials: S
authors.lastname: Bloom
authors.forename: Marco
authors.initials: M
authors.lastname: Novelli
authors.forename: Steve
authors.initials: S
authors.lastname: Halligan
authors.forename: Manuel
authors.initials: M
authors.lastname: Rodriguez-Justo
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Taylor
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000465:Algorithms; D003424:Crohn Disease / Q000473:pathology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007416:Intestinal Perforation / Q000473:pathology; D007421:Intestine, Small / Q000293:injuries / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D055815:Young Adult