Object: 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.
Materials and 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 %).
Conclusion: 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.