MR Enterography in Crohnʼs Disease: Comparison of Contrast Imaging with Diffusion-weighted Imaging and a special Form of Color Coding

AbstractWe compared contrast-enhanced MR enterography with diffusion-weighted sequences to evaluate the validity of diffusion-weighted sequences for activity assessment in Crohnʼs disease compared to endoscopy. In addition, we investigated a new color-coded image post-processing technique in comparison with standard sequences and endoscopy.Included were 197 MR enterographies (2015–2017) performed by using standardized examination protocols. The intestine was divided into 7 segments, which were compared separately. The accuracy of the MR examinations with regard to disease activity was validated using the Seo and MaRIA score and endoscopy findings. In addition, the image data were post-processed using a color-coded evaluation method (DCE tool on OsiriX).The comparison between contrast-enhanced and diffusion-weighted sequences showed a highly significant correlation for all bowel sections with a mean Spearman correlation coefficient of 0.876 (0.809–0.928). The color-coded image post-processing showed a sensitivity of 83.2 % and a specificity of 70.5 % in comparison with the MaRIA score. In comparison to endoscopy, a sensitivity of 81.3 % and a specificity of 70.5 %. In comparison with endoscopy, the MaRIA score showed a sensitivity of 80.2 % and a specificity of 84.0 % at a cut-off of 7. The visual score according to Seo showed a sensitivity of 85.7 % with a specificity of 77.0 % in the contrast-weighted examination and a sensitivity of 87.9 % and a specificity of 71.8 % for diffusion weighted images.Diffusion-weighted sequences are as good as contrast-weighted sequences for assessing inflammatory activity in Crohnʼs disease. Contrast is often helpful for assessing complications, but this was not the purpose of this study. Visual imaging using color-coded data sets was similarly good at detecting inflammation.