Evaluation of diffusion-weighted MR imaging for detection of bowel inflammation in patients with Crohn's disease.

RATIONALE AND OBJECTIVES The aims of this study were to determine the feasibility of diffusion-weighted magnetic resonance imaging (DWI) in the detection of bowel inflammation and to investigate the changes in apparent diffusion coefficient (ADC) values in the inflamed bowel in patients with Crohn's disease. MATERIALS AND METHODS Eleven patients who underwent magnetic resonance enterography (including DWI) for Crohn's disease and colonoscopy or surgery within 4 weeks of examination were recruited. Two radiologists reviewed diffusion-weighted images and ADC maps to evaluate for inflammation in each bowel segment (terminal ileum, cecum, ascending colon, transverse colon, descending colon, and rectosigmoid colon) and measured the ADC values of each bowel segment. Endoscopic and pathologic results were correlated with DWI findings. RESULTS Fifty-three segments (19 with inflammation, 34 normal) were included. DWI detected inflammation in 18 of 19 segments (94.7%) and showed normal results in 28 of 34 segments (82.4%). On diffusion-weighted images, bowel segments with inflammation revealed higher signal compared to normal segments. Artifact levels were none or minimal in 10 of 11 patients (90.9%) and moderate in one patient. On quantitative analysis, ADC values of inflamed and normal bowel were measured as 0.47 - 2.60 x 10(-3) and 1.39 - 4.03 x 10(-3) mm(2)/s, respectively (P < .05). CONCLUSION DWI with parallel imaging is a feasible technique for the detection of inflammation in patients with Crohn's disease. ADC values are decreased in inflamed bowel segments, indicating restricted diffusion.