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, Caractérisation des masses médiastinales antérieures en IRM avec séquence de diffusion

. Objectif, Évaluer la performance de l'IRM avec séquences de déplacement chimique et de diffusion dans la caractérisation masses médiastinales antérieures (MMA)

. Méthode, Résultats : 64 patients ont été inclus, 20 avaient une MMA bénigne, 44 une MMA non-typiquement bénigne. Les valeurs de CSR et d'ADC différaient significativement entre les groupes (p<0,01). Les valeurs seuil optimales de CSR et d'ADC étaient respectivement de 0,885 (sensibilité 93,5%, spécificité 88,9%) et de 1,3 10-3 mm 2 /sec (sensibilité 73,3%, spécificité 87,5%). La probabilité d'avoir une MMA non-typiquement bénigne augmentait avec le CSR (p=0,02) et diminuait avec l'augmentation de l'ADC (p=0,04), Étude rétrospective des patients adressés pour une MMA entre 2000 et 2017. Les MMA étaient bénignes (rebonds thymiques, lipome, hyperplasie simple) et non-typiquement bénignes (malignes ou nécessitant des explorations complémentaires). Les tumeurs épithéliales thymiques étaient réparties en thymomes de bas-risque (A, AB, B1), haut-risque (B2, B3) et carcinomes thymiques

, Purpose : To assess the effectiveness of MRI using chemical-shift sequence and DWI to characterize mediastinal anterior masses (MAM)

, Qualitative analysis of morphological criteria and quantitative analysis of the chemical-shift ratio (CSR) and Apparent Diffusion Coefficient (ADC) were performed. The discrimination capacity of CSR and ADC was evaluated with ROC curves and optimal cutoff points were determined according to the Youden index. The relationship between diagnosis and MRI findings were evaluated with logistic regression models. Results: 64 patients were eligible, 20 with benign MAM (9 males, 11 females, mean age 30.7 years) and 44 with a non-typically benign MAM (25 males, 19 females, mean age 56.7 years). CSR and ADC significantly differed between groups (P<0.01). The CSR optimal cutoff point was 0.885 (sensitivity 93.5%, specificity 88.9%). The ADC optimal cutoff point was 1.3 10-3 mm 2 /sec (sensitivity 73.3%, specificity 87.5%). MAM tumor probability increased with higher CSR (P=0.02) and lower ADC, Methods: A retrospective analysis was performed of patients referred for a MAM between 2000 and 2017. Patients were classified as benign (rebounds, lipoma, normal thymus) and a 'non-typically benign' (lesions needing further investigations or malignant) MAM

T. Mediastinum and M. , Université Paris Descartes Faculté de Médecine Paris Descartes 15