P129 Value of diffusion-weighted magnetic resonance enterocolonography for assessing Crohn’s disease activity

Background We aimed to determine diffusion-weighted imaging (DWI) value to predict active Crohn’s disease (CD) and compare apparent diffusion coefficients (ADC) with endoscopic and conventional magnetic resonance imaging (MRI) CD activity indices. Methods Overall, 229 patients with suspected CD prospectively underwent magnetic resonance enterocolonography (MR-EC) with DWI sequence and ileocolonoscopy. Magnetic resonance activity index (MaRIA), Clermont index, and CD endoscopic index of severity (CDEIS) were calculated. Results Out of 229 investigated patients, the clinical diagnosis of CD was confirmed in 100 persons. Using receiver operating characteristic curve, we showed that DWI score ≥2 had 96.9% sensitivity and 82.3% specificity for diagnosing CD. A threshold of ADC value of 1.30×10–3mm2/s can distinguish between normal and inflamed bowel segments with a sensitivity of 73.8% and a specificity of 98% using Copenhagen diagnostic criteria as the reference standard. While using MaRIA, the threshold of ADC value was established of 1.32 × 10–3 mm2/s with sensitivity and specificity (97.9%, 97.8%). ADC correlated with MaRIA-G (global) (r = -0.69, p = 0.001), Clermont-G (r = -0.722, p = 0.001) and CDEIS (r = -0.69, p = 0.001). Conclusion DWI is a valuable tool which is able to identify inflamed bowel segments as accurate as conventional MARIA score and to discriminate between mild and moderate and severe CD activity.