Valeur de l’entéro-IRM avec injection de gadolinium dans la maladie de Crohn en pédiatrie : étude préliminaire

Abstract

Objective Feasibility study of contrast enhanced MR enterography without enteroclysis as a new diagnostic tool for children with known or suspected Crohn's disease. Methods We prospectively included 15 children, 8-18 years old, with clinical suspicion of Crohn's disease. MR enterography without enteroclysis was performed on a 1,5 T clinical MR system. A total of 1000 ml of mannitol 5% was orally administered 60 minutes prior to MRI. Coronal and axial breath-hold sequences were acquired. The following sequences were obtained: True-FISP, FLASH T1 2D/3D with Fat saturation before and after gadolinium injection. Two radiologists, blinded to patient information, independently reviewed all examinations to record image quality, the degree of distension of the distal ileum, the presence of abnormal bowel segments and the presence of extra-intestinal complications. MRI findings were correlated to sonographic, endoscopic and biological results (sensitivity, specificity, Kappa test). Results The examinations were considered of satisfactory diagnostic quality in 93.3% of patients. Respiratory artifacts were present in one case. The entire GI tract could be identified on all sequences. Distention of the distal ileum was recorded as good to excellent in 89% of healthy subjects. Five MR examinations were considered abnormal with isolated ileal involvement in 2 cases, ileocolic involvement in 2 cases, and isolated colonic involvement in 1 case. The sensitivity and specificity of MR for the positive diagnosis of Crohn's disease were 100% and 83% respectively. Three extra-intestinal complications were detected: one case of ileo-ileal fistula, not identified on ultrasonography, an asymptomatic anal fistula and a symptomatic inflammatory stricture. Conclusion MR enterography without enteroclysis is a well tolerated, effective non invasive method in the evaluation of known or suspected Crohn's disease. Because of the absence of ionizing radiation, MR enterography should become the gold standard in pediatric patients.