title: Impact of gadolinium-based contrast agent in the assessment of Crohn's disease activity: Is contrast agent injection necessary?
abstract: OBJECTIVE
  To determine whether magnetic resonance enterography (MRE) performed without intravenous contrast injection is diagnostically noninferior to conventional contrast-enhanced MRE (CE-MRE) in patients with Crohn's disease (CD).
  
  
  METHODS
  This was an Institutional Review Board (IRB)-approved retrospective study. Ninety-six patients (52 male and 44 female; 47.18 years ± 13.6) with a diagnosis of CD underwent MRE at 1.5T including T2 -weighted single-shot turbo-spin-echo, T2 -weighted spectral fat presaturation with inversion recovery (SPAIR), T1 -weighted balanced fast-field-echo MR sequences, and CE-MRE consisting in T1 -weighted breath-hold THRIVE 3D MRI sequences after administration of gadobenate dimeglumine (0.2 mL/kg of body weight). Unenhanced MRE, CE-MRE, and unenhanced MRE plus CE-MRE were reviewed in separate sessions with blinding by two readers in consensus, and subsequently by two other readers independently considering a subgroup of 20 patients. Crohn's Disease Endoscopic Index of Severity (CDEIS) and/or histologic analysis of the surgical specimen were considered as reference standards for the assessment of inflammatory activity.
  
  
  RESULTS
  Patients revealed prevalently active (n = 55 patients) or quiescent CD (n = 41 patients). The agreement between unenhanced MRE vs. CE-MRE in interpreting active bowel inflammation was 96% (123/128 bowel segments; one-sided 95% confidence interval [CI], >94.4%). Unenhanced MRE vs. CE-MRE vs. unenhanced MRE plus CE-MRE revealed a diagnostic accuracy of 93% [90/96] vs. 92% [88/96] vs. 97% [93/96] (P > 0.05) in the diagnosis of active CD. Interreader agreement was very good for all variables (κ value = 0.8-0.9) except for the measurement of the length of disease (κ value = 0.45).
  
  
  CONCLUSIONS
  Unenhanced MRE was noninferior to CE-MRE in diagnosing active inflammation in patients with CD.
authors.affiliation: Department of Radiology, Cattinara Hospital, University of Trieste, Trieste, Italy.
authors.forename: Emilio
authors.initials: E
authors.lastname: Quaia
authors.affiliation: Department of Gastroenterology, Cattinara Hospital, Trieste, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Sozzi
authors.affiliation: Department of Radiology, Cattinara Hospital, University of Trieste, Trieste, Italy.
authors.forename: Antonio Giulio
authors.initials: AG
authors.lastname: Gennari
authors.affiliation: Department of Radiology, Cattinara Hospital, University of Trieste, Trieste, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Pontello
authors.affiliation: Department of Radiology, Cattinara Hospital, University of Trieste, Trieste, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Angileri
authors.affiliation: Department of Radiology, Cattinara Hospital, University of Trieste, Trieste, Italy.
authors.forename: Maria Assunta
authors.initials: MA
authors.lastname: Cova
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media / Q000737:chemistry*; D003424:Crohn Disease / Q000000981:diagnostic imaging* / Q000473:pathology; D004724:Endoscopy; D005260:Female; D005682:Gadolinium / Q000737:chemistry*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007249:Inflammation; D007275:Injections, Intravenous; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015588:Observer Variation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D003287:Contrast Media; D005682:Gadolinium
keywords: Crohn's disease; enterography; inflammatory bowel diseases; magnetic resonance imaging