Background: To evaluate the use of low-field magnetic resonance imaging (MRI) in active inflammatory bowel disease (IBD).
Methods: MRI was executed in a consecutive cohort of 28 patients with Crohn disease (CD) and in 17 with ulcerative colitis (UC) prior to glucocorticoid treatment (1 mg prednisolone orally/kg body weight/day). MRI was repeated after 2-3 weeks (22 CD, 12 UC), and again after treatment completion or prior to surgery (18 CD, 6 UC). Five bowel segments were evaluated separately. MRIs were blindly evaluated by two observers, and findings compared with 39 leucocyte scintigraphies, 38 endoscopies, 15 double-contrast barium enemas, 66 small-bowel radiographic examinations and surgery in 23 patients.
Results: In CD, blinded evaluation revealed a kappa (kappa) of 0.84 (95% confidence interval (CI) 0.78-0.91). In UC, kappa was 0.66 (95% CI 0.55-0.78). Agreements regarding disease extension between MRI and other modalities in CD were found in 345 bowel segments out of 391 (88.2%) at risk, and in UC in 209/235 (88.9%). Colonic disease activity gradings by radiography and endoscopy correlated significantly with T2-signal intensity (SI(T2)) and increments in T1-signal intensity (%SI(T1)) in both diseases. Significant correlations between MRI indices of disease activity and CDAI in CD (MRI-SI(T2): P <0.0001: MRI% SI(T1): P=0.0008) and the Powell-Tuck index in UC (MRI% SI(T1): P=0.008) were found.
Conclusions: With low interobserver variation and high concordance of findings with other examinations. low-field MRI seems a valuable modality in active IBD. In addition, MRI expressions of disease activity correlate to clinical, radiographic and endoscopic disease activity.