Free-breathing diffusion-weighted imaging for the assessment of inflammatory activity in Crohn's disease

Purpose To investigate the application of free‐breathing diffusion‐weighted MR imaging (DWI) to the assessment of disease activity in Crohn's disease. Materials and Methods Thirty‐one patients with Crohn's disease were investigated using free‐breathing DWI without special patient preparation or IV or intraluminal contrast agent. The bowel was divided into seven segments, and disease activity was assessed visually on DWI. For quantitative analysis, the apparent diffusion coefficient (ADC) was measured in each segment. The findings of a conventional barium study or surgery were regarded as the gold standard for evaluating the diagnostic ability of DWI to assess disease activity. Results Upon visual assessment, the sensitivity, specificity, and accuracy for the detection of disease‐active segments were 86.0, 81.4, and 82.4%, respectively. In the quantitative assessment, the ADC value in the disease‐active area was lower than that in disease‐inactive area in small and large bowels (1.61 ± 0.44×10−3 mm2/s versus 2.56 ± 0.51 × 10−3 mm2/s in small bowel and 1.52 ± 0.43 × 10−3 mm2/s versus 2.31 ± 0.59 × 10−3 mm2/s in large bowel, respectively, P