title: Crohn's disease Activity: Abdominal Computed Tomography Histopathology Correlation.
abstract: OBJECTIVE
  Crohn's disease is a type of inflammatory bowel disease affecting estimated 4 million people worldwide. Therapy stratification of Crohn's disease (CD) is mainly based on the inflammatory activity being assessed by endoscopic biopsy and clinical criteria. Cross-sectional imaging allows for the assessment of structural characteristics of the entire gastrointestinal tract including small bowel loops and may provide potential non-invasive image-based biomarkers for the inflammatory activity of CD. The aim of this study was to explore the predictive value of Computed Tomography-based morphologic patterns for inflammatory activity in CD.
  
  
  METHODS
  42 patients diagnosed with CD were included in a retrospective study (13 male, 29 female, median age 32 years). Abdominal CT imaging was carried out on symptomatic patients at a single institution 0-10 days prior to endoscopic biopsy or surgery using a protocol optimized for the characterization of structural bowel alterations. Image data were initially reviewed independently by three radiologists and discrepancies were settled in consensus with a focus on mesenteric fat stranding and combing, mesenteric adenopathy, mesenteric abscess, intraperitoneal free fluid, fistula, skip lesions, highest wall thickness and the localization of the affected bowel. The extent of inflammatory activity in the bowel wall was determined subsequently by histological analysis.
  
  
  RESULTS
  All intestinal and extraintestinal CT findings except the mesenteric comb sign showed a tendency towards higher extent or prevalence in patients with high histological inflammatory activity score, especially median bowel wall thickness (6.0 mm vs. 3.5 mm), mesenteric abscesses (32% vs. 0%) and mesenteric adenopathy (94% vs. 45%). Spearman rank order correlation coefficient indicated a significant correlation of bowel wall thickness (r = 0.40, p < 0.05), mesenteric adenopathy (r = 0.54, p < 0.05), mesenteric abscess (r = 0.33, p < 0.05) and mesenteric fat stranding (r = 0.33, p < 0.05) with the histological inflammatory activity score.
  
  
  CONCLUSIONS
  CT-based biomarkers including wall thickness, mesenteric fat stranding, mesenteric lymphadenopathy and mesenteric abscess positively correlated with the histological inflammatory activity score and therefore provided additional information for therapy stratification in symptomatic patients with CD, particularly as most of these biomarkers are hidden from endoscopy.
authors.affiliation: Zentrum für Medizinische Radiologie, Röntgeninstitut Cham, Rigistrasse 1, CH-6330 Cham, Switzerland.
authors.forename: N
authors.initials: N
authors.lastname: Paquet
authors.affiliation: Department of Pathology, Brigham and Women's Hospital, Boston, MA, United States.
authors.forename: J N
authors.initials: JN
authors.lastname: Glickman
authors.affiliation: Department of Radiology, Sisli Etfal Education and Research Hospital, Etfal Sok Istanbul, 80220 Istanbul, Turkey.
authors.forename: S M
authors.initials: SM
authors.lastname: Erturk
authors.affiliation: Department of Radiology, University Hospitals Case Medical Center/Case Western Reserve University, 11100 Euclid Avenue, Mailstop: BSH 5056, 44106 Cleveland, OH, United States.
authors.forename: P R
authors.initials: PR
authors.lastname: Ros
authors.affiliation: Department of Radiology, Inselspital Bern, University of Bern, 3010 Bern, Switzerland.
authors.forename: J T
authors.initials: JT
authors.lastname: Heverhagen
authors.affiliation: Department of Radiology, Inselspital Bern, University of Bern, 3010 Bern, Switzerland; Department of Radiology, Hirslanden Clinics Zürich, Witellikerstrasse 40, 8032 Zürich, Switzerland.
authors.forename: M A
authors.initials: MA
authors.lastname: Patak
keywords: CT Crohn Small bowel Computed Tomography; Histopathology