title: Can Contrast-Enhanced Sonography Detect Bowel Wall Fibrosis in Mixed Inflammatory and Fibrotic Crohn Disease Lesions in an Animal Model?
abstract: OBJECTIVE
  To determine whether contrast-enhanced sonographic quantitative perfusion parameters can detect bowel wall fibrosis in the setting of mixed inflammatory and fibrotic lesions in a Crohn disease animal model.
  
  
  METHODS
  This study was approved by the institutional Committee on the Use and Care of Animals. Multiple (range, 1-5) 2,4,6-trinitrobenzenesulfonic acid-ethanol enemas were used to create intestinal inflammatory lesions with variable fibrosis in female Lewis rats. Low-mechanical index contrast-enhanced sonography was performed 3 days after the final enema using a 0.2-mL bolus of sulfur hexafluoride microbubbles injected through a tail vein. Contrast-enhanced sonographic data were analyzed with software that converts video data into echo-power (linearized) data. Colorectal lesions were scored for histopathologic inflammation and fibrosis; bowel wall collagen was quantified by Western blotting. The Spearman correlation was used to assess associations between contrast-enhanced sonographic quantitative parameters and bowel wall collagen; the Kruskal-Wallis test was used to compare continuous results between histopathologic groups.
  
  
  RESULTS
  Thirty-one animals were included in our analysis. Animals were placed into 3 histopathologic cohorts: (1) severe bowel wall inflammation/minimal or no fibrosis (n = 11); (2) severe bowel wall inflammation/moderate fibrosis (n = 9); and (3) severe bowel wall inflammation/severe fibrosis (n = 11). Western blotting showed a significant difference in bowel wall collagen between histopathologic cohorts (P = .0001). There was no correlation between any contrast-enhanced sonographic quantitative parameter and bowel wall collagen (P > .05). There was no difference between histopathologic cohorts for any contrast-enhanced sonographic quantitative parameter (P > .05).
  
  
  CONCLUSIONS
  Contrast-enhanced sonographic quantitative perfusion parameters failed to effectively detect bowel wall fibrosis in the setting of superimposed inflammation in a Crohn disease animal model.
authors.affiliation: Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Dillman
authors.affiliation: Department of Radiology, University of Michigan Health System, Ann Arbor, Michigan, USA.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Rubin
authors.affiliation: Department of Internal Medicine, University of Michigan Health System, Ann Arbor, Michigan, USA.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Johnson
authors.affiliation: Department of Pathology, University of Michigan Health System, Ann Arbor, Michigan, USA.
authors.forename: David S
authors.initials: DS
authors.lastname: Moons
authors.affiliation: Department of Internal Medicine, University of Michigan Health System, Ann Arbor, Michigan, USA.
authors.forename: Peter D R
authors.initials: PD
authors.lastname: Higgins
mesh_terms: D000818:Animals; D003287:Contrast Media; D003424:Crohn Disease / Q000000981:diagnostic imaging* / Q000473:pathology; D004195:Disease Models, Animal; D005260:Female; D005355:Fibrosis / Q000000981:diagnostic imaging / Q000473:pathology; D007089:Image Enhancement / Q000379:methods*; D007249:Inflammation / Q000000981:diagnostic imaging / Q000473:pathology; D007422:Intestines / Q000000981:diagnostic imaging* / Q000473:pathology*; D051381:Rats; D011917:Rats, Inbred Lew; D015203:Reproducibility of Results; D014463:Ultrasonography / Q000379:methods*
chemical_list: D003287:Contrast Media
keywords: Crohn disease; animal model; contrast-enhanced sonography; fibrosis; gastrointestinal ultrasound; inflammation; microbubble contrast agent