Can MR Enterography and Diffusion-Weighted Imaging Predict Disease Activity Assessed by Simple Endoscopic Score for...

Monitoring Crohn's disease (CD) activity has a crucial importance, especially for evaluating treatment efficacy. Magnetic resonance enterography (MRE) and diffusion-weighted imaging (DWI) or their combination may represent potential non-invasive tools for this purpose. This study aimed to examine DWI and MRE for their potential to differentiate between different grades of ileocolonic CD activity.

This retrospective study included 54 adult patients with a diagnosis of CD who underwent ileocolonoscopy and MRE including the DWI sequence. The severity of CD inflammation was categorized by Simple Endoscopic Score for Crohn's Disease (SES-CD) as inactive, mild, moderate and severe. In addition, following conventional MRE and DWI parameters were examined: bowel wall thickness, mural T2 hyperintensity, contrast enhancement, DWI signal intensity, and apparent diffusion coefficient (ADC) values.

In patients with moderate to severe disease based on SES-CD, T2 hyperintensity score [1.68 ± 0.77 (1-3) vs. 2.19 ± 0.69 (1-3); p = 0.013] and mean DWI score [2.42 ± 0.58 (1-3) vs. 2.04 ± 0.69 (1-3); p = 0.037 ] were higher and mean ADC values [1.5 ± 0.4 (0.9-2.5) vs. 1.2 ± 0.3 (0.6-1.8)] were lower compared to patients with inactive to mild CD. ADC had a moderate diagnostic accuracy in predicting moderate to severe disease (AUC = 0.729, 95% CI = 0.591-0.841, p = 0.001), with a cut-off value of ≤1.47 × 10^-3 mm²/sec yielded 88.5% (23/26) sensitivity, 57.1% (16/28) specificity.

DWI, ADC and T2 signal appear to differentiate moderate to severe CD from inactive to mildly active CD, based on SES-CD evaluation and may be useful in monitoring disease activity, particularly when evaluating treatment response.