MRI and Multidetector CT in Crohn’s disease

Purpose: to evaluate diagnostic capabilities of Magnetic Resonance Imaging (MRI) and Multidetector Computed Tomography (MDCT) in Crohn’s disease (CD). Methods and Materials: 30 consecutive patients with known or suspected CD underwent MRI and MDCT of the small bowel. MR and CT examinations were performed after oral administration of polyethylene-glycol balanced solution. MRI protocol included T2-weighted SSFSE and Gd-enhanced T1-weighted fat-suppressed 3D FAME sequences. MDCT scans were acquired at baseline and 50 seconds after i.v. administration of 110-130 ml non ionic iodinated contrast medium. MR and CT scans were blindly evaluated by two radiologists and compared with conventional enteroclysis (CE), endoscopy and histology findings available in all patients and considered as the gold standard. Results: disease prevalence was 86,7%. MRI showed accuracy of 93,3%, sensitivity of 95,5% (CI 86,8%-104,2%), specificity of 87,5% (CI 64,6%-110,4%), predictive positive value (PPV) of 95,5%, predictive negative value (NPV) of 87,5%. MDCT showed accuracy of 90%, sensitivity of 90,9% (CI 78,9%-102,9%), specificity of 87,5% (CI 64,6%-110,4%), PPV of 95,2%, NPV of 77,8%. MR and MDCT enabled identification of extra-intestinal disease: abscess, mesenteric fibrofatty proliferation, lymphadenopathy, increased perienteric vascularity. MR-fluoroscopy provided functional information about intestinal distension and motility. Conclusion: MRI, MDCT and CE are complementary methods for diagnosing small bowel CD. Because of the lack of radiation exposure, MRI should be used as the preferred method for follow-up of patients with CD.