INTRODUCTION: Diffusionweighted magnetic resonance imaging has the potential to identify inflamed bowel segments in patients with Crohn disease (CD).
OBJECTIVES: We aimed to determine diffusionweighted imaging (DWI) value to predict active CD and compare apparent diffusion coefficients (ADCs) with endoscopic and conventional indices of magnetic resonance imaging of CD activity . PATIENTS AND
METHODS: Overall , 229 patients with suspected and diagnosed CD prospectively underwent magnetic resonance enterocolonography (MREC) with DWI sequence and ileocolonoscopy . The magnetic resonance activity index (MaRIA), Clermont index, and CD endoscopic index of severity (CDEIS) were calculated .
RESULTS: The clinical diagnosis of CD was confirmed in 100 out of 229 patients . A DWI score of 2 or higher had 96.9% sensitivity and 82.3% specificity for diagnosing CD . A threshold ADC value of 1.3 × 10-3 mm2/s could distinguish between normal and inflamed bowel segments with a sensitivity of 73.8% and a specificity of 98% . For the MaRIA, a threshold ADC value of 1.32 × 10-3 mm2/s with a sensitivity of 97.9% and a specificity of 97.8% was established . There were significant differences in the DWI scores and ADC values comparing patients with inactive, mild, and moderate-to-severe disease (P <0.01). ADCs inversely correlated with the MaRIAglobal (r = -0.69; P = 0.001), Clermontglobal (r = -0.722; P = 0.001), and CDEIS (r = -0.69; P = 0.001).
CONCLUSIONS: DWI is a valuable tool that is capable of identifying inflamed bowel segments as accurately as the conventional MaRIA score and of discriminating between mild and moderate-to-severe CD.