DWI BOWEL RATIOS: NEW INDEXES FOR CROHN’S DISEASE ACTIVITY AT MAGNETIC RESONANCE ENTEROGRAPHY?

Crohn’s disease is an intestinal chronic inflammatory condition of uncertain etiology and clinically characterized by alternation of recurrence and remission periods. The main pathologic finding consists in a transmural inflammation of the intestinal wall that can involve any segment of the gut, especially the small bowel. Final diagnosis of Crohn’s disease is achieved combining clinical picture, laboratory tests and endoscopy with biopsy. Among all the imaging modalities, Magnetic Resonance Enterography is capable in providing a comprehensive assessment of the the intestinal loops as well as the abdominal cavity without employing ionizing radiations. Therefore, it is currently considered the imaging technique of choice for evaluating CD patients. Over the years, apparent diffusion coefficient maps based on diffusion-weighted images have been investigated in order to distinguish the diverse active inflammation degrees. However, quantitative assessment on apparent diffusion coefficient maps usually shows different results related to the various vendors and can be impaired by technical artifacts. Therefore, no standardizable values have been found so far. The aim of this work is to test the effectiveness of numerical values measured within the affected bowel wall on diffusion-weighted images in relation to those of the mesenteric lymph nodes, the spleen and the psoas muscle, thorugh the calculation of mathematical ratios. Endoscopy was chosen as the reference standard. This work demonstrates a statistically significant correlation between endoscopic classes and diffusion-weighted imaging ratios measured on ileum, lymph nodes and spleen in non-operated Crohn’s disease patients.