title: Active Crohn's disease in the small bowel: evaluation by diffusion weighted imaging and quantitative dynamic contrast enhanced MR imaging.
abstract: OBJECTIVE
  To determine relative diagnostic value of MR diffusion and perfusion parameters in detection of active small bowel inflammation in patients with Crohn's disease (CD).
  
  
  METHODS
  We reviewed 18 patients with active CD of terminal ileum (TI) who underwent MR enterography (MRE; including dynamic contrast enhanced MRI and diffusion-weighted MRI). Conventional MRI findings of TI were recorded. Regions of interest were drawn over TI and normal ileum to calculate apparent diffusion coefficient (ADC), the volume transfer constant (K(trans)) and the contrast media distribution volume (v(e)). Receiver operating characteristic analysis was used to determine their diagnostic performance.
  
  
  RESULTS
  Among conventional MR findings, mural thickening and increased enhancement were present in all actively inflamed small bowel. K(trans), v(e), and ADC values differed significantly between actively inflamed TI and normal ileum (0.92 s(-1) versus 0.36 s(-1); 0.31 versus 0.15 ± 0.08; 0.00198 mm(2)/s versus 0.00311 mm(2)/s; P < 0.001). Area under the curve (AUC) for K(trans), v(e), and ADC values ranged from 0.88 to 0.92 for detection of active inflammation. Combining K(trans) and ADC data provided an AUC value of 0.95.
  
  
  CONCLUSIONS
  Dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted imaging (DWI) provide quantitative measures of small bowel inflammation that can differentiate actively inflamed small bowel segments from normal small bowel in CD. DWI provides better sensitivity compared with DCE-MRI and combination of ADC and K(trans) parameters for analysis can potentially improve specificity.
authors.affiliation: Department of Radiology, The University of Chicago, Chicago, Illinois, USA. aoto@radiology.bsd.uchicago.edu
authors.forename: Aytekin
authors.initials: A
authors.lastname: Oto
authors.forename: Arda
authors.initials: A
authors.lastname: Kayhan
authors.forename: Joshua T B
authors.initials: JT
authors.lastname: Williams
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Fan
authors.forename: Laura
authors.initials: L
authors.lastname: Yun
authors.forename: Sanaz
authors.initials: S
authors.lastname: Arkani
authors.forename: David T
authors.initials: DT
authors.lastname: Rubin
mesh_terms: D000328:Adult; D019540:Area Under Curve; D001706:Biopsy; D003287:Contrast Media / Q000494:pharmacology*; D003424:Crohn Disease / Q000175:diagnosis* / Q000473:pathology*; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D004724:Endoscopy / Q000379:methods; D005260:Female; D006801:Humans; D007082:Ileum / Q000473:pathology; D007249:Inflammation; D007421:Intestine, Small / Q000378:metabolism*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D012372:ROC Curve
chemical_list: D003287:Contrast Media