Role of magnetic resonance enterocolonography with diffusion in the assessment of inflammatory bowel diseases activity

Abstract Background This study aimed to determine whether diffusion-weighted Magnetic Resonance Enterocolonography DWI MREC) can accurately assess the degree of disease activity in patients with inflammatory bowel diseases (IBDs), and whether it can serve as a non-invasive alternative to endoscopic evaluation, especially by correlating DWI findings with histopathology and the Mayo Endoscopic Score (MES) in ulcerative colitis (UC) patients. Methods This prospective study enrolled 50 patients diagnosed with active IBD, including 35 with crohn’s disease (CD) and 15 with ulcerative colitis (UC). The participants ranged in age from 9 to 72 years (median: 29 years) and included 36 females and 14 males. All patients underwent DWI MREC on a 1.5 T MRI scanner and ileocolonoscopy, with biopsies performed within one week of imaging. DWI was conducted at a b-value of 800 mm 2 /s, and apparent diffusion coefficient (ADC) values were quantitatively assessed. Disease activity was graded histopathologically and correlated with ADC values. In UC patients, DWI results were further compared with MES. Receiver operating characteristic (ROC) curve analysis was used to evaluate diagnostic performance. Results Mean ADC values in diseased segments were 0.98 ± 0.18 × 10⁻ 3 mm 2 /s in CD and 0.99 ± 0.11 × 10⁻ 3 mm 2 /s in UC, with no significant difference between the groups ( P= 0.805). However, significant negative correlations were observed between ADC values and disease activity grades in both CD ( P= 0.025) and UC ( P= 0.002). ROC analysis revealed good discrimination between mild and moderate-to-severe disease (AUC=0.741, P= 0.012) at a cutoff ADC >1.04 with 75.0% sensitivity and 81.6% specificity. In UC patients, ADC values correlated significantly with MES (r = − 0.539, P= 0.038). Conclusion DWI MREC provides a non-invasive, reliable tool for differentiating mild from moderate-to-severe IBD activity, showing strong potential to complement or replace endoscopy, especially in acute settings or for therapy monitoring.