title: Magnetization transfer for the assessment of bowel fibrosis in patients with Crohn's disease: initial experience.
abstract: OBJECTIVE
  To assess the feasibility of magnetization transfer (MT) imaging of the bowel wall in patients with Crohn's disease (CD), and to evaluate its utility for the detection of intestinal fibrosis.
  
  
  METHODS
  In this prospective study, 31 patients (age 39.0 ± 13.2 years) with CD were examined in a 1.5T MR scanner. To establish a standard of reference, two independent readers classified the patients in different disease states using standard MR enterography, available clinical data and histological findings. In addition to the standard protocol, a 2D gradient-echo sequence (TR/TE 32 ms/2.17 ms; flip angle 25°) with/without 1,100 Hz off-resonance prepulse was applied. MT ratios (MTR) of the small bowel wall were computed off-line on a pixel-by-pixel basis.
  
  
  RESULTS
  The MT sequences acquired images of sufficient quality and spatial resolution for the evaluation of the small bowel wall without detrimental motion artefacts. In normal bowel wall segments, an intermediate MTR of 25.4 ± 3.4 % was measured. The MTR was significantly increased in bowel wall segments with fibrotic scarring (35.3 ± 4.0 %, p < 0.0001). In segments with acute inflammation, the mean MTR was slightly smaller (22.9 ± 2.2 %).
  
  
  CONCLUSIONS
  MT imaging of the small bowel wall is feasible in humans with sufficient image quality and may help with the identification of fibrotic scarring in patients with CD.
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Rämistr. 100, 8091 Zurich, Switzerland. shila.pazahr@usz.ch
authors.forename: Shila
authors.initials: S
authors.lastname: Pazahr
authors.forename: Iris
authors.initials: I
authors.lastname: Blume
authors.forename: Pascal
authors.initials: P
authors.lastname: Frei
authors.forename: Natalie
authors.initials: N
authors.lastname: Chuck
authors.forename: Daniel
authors.initials: D
authors.lastname: Nanz
authors.forename: Gerhard
authors.initials: G
authors.lastname: Rogler
authors.forename: Michael
authors.initials: M
authors.lastname: Patak
authors.forename: Andreas
authors.initials: A
authors.lastname: Boss
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000465:Algorithms; D003424:Crohn Disease / Q000473:pathology*; D005260:Female; D005355:Fibrosis; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007422:Intestines / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult