Magnetic resonance imaging to distinguish the type and severity of pediatric inflammatory bowel diseases

Background: The distinction between ulcerative colitis and Crohn's disease is important, because treatment options and clinical course may vary. Magne tic resonance imaging (MRI) allows noninvasive transmural assessment of the intestine and may facilitate differentiation of ulcerative colitis from Cr ohn's disease. The objective of this prospective study was to determine whe ther MRI differentiates Crohn's disease from ulcerative colitis in children as effectively as colonoscopy with mucosal biopsies. Methods: Fifteen patients underwent colonoscopy with biopsies followed by a bdominal MRI. The MRI diagnosis, determined by two radiologists independent ly completing a standardized form was compared with the gastroenterologic d iagnosis. Results: After colonoscopy and review of histology, Crohn's disease was dia gnosed in nine patients, ulcerative colitis in five, and indeterminate coli tis in one, who was excluded from study. Agreement of the MRI diagnosis wit h the gastroenterologic diagnosis was 4 of 4 (100%) for ulcerative colitis, 4 of 10 (40%) for Crohn's disease considering both radiologists, and 5 of 10 (50%) for Crohn's disease for each radiologist individually. Percentage of enhancement by MRI did nor correlate with the severity of inflammation d etermined at endoscopy among the patients with Crohn's disease (r = -0.3, P = 0.366). There was agreement on severity of inflammation in three of four patients with ulcerative colitis. Conclusions: Current MRI interpretation of inflammatory bowel disease did n ot adequately recognize Crohn's disease in children. Therefore, colonoscopy with biopsy remains the most accurate tool for determining the type and se verity of inflammatory bowel disease in children and adolescents.