CHARACTERIZATION OF ADRENAL MASSES WITH CHEMICAL-SHIFT AND GADOLINIUM-ENHANCED MR-IMAGING

PURPOSE: To assess the potential role of chemical shift and dynamic ga dolinium-enhanced magnetic resonance (MR) imaging in the characterizat ion of adrenal masses. MATERIALS AND METHODS: Fifty-one adrenal masses (35 adenomas and 16 nonadenomas) in 43 patients were evaluated with c hemical shift MR imaging, dynamic gadolinium-enhanced MR imaging, or b oth. The relative change in the signal intensity (SI) ratio of the adr enal mass to liver and paraspinal muscles was quantitatively and quali tatively assessed. Opposed-phase gradient-echo (GRE) images were compa red with in-phase images. RESULTS: With qualitative visual inspection, only adenomas showed a decrease in relative SI ratio on opposed-phase chemical shift images (specificity, 100%; sensitivity, 81%). Quantita tive ratios corresponding to 100% specificity were also observed, with similar sensitivities. Adenomas could not be differentiated from nona denomas with visual assessment of maximum SI after contrast material a dministration or washout. CONCLUSION: Characterization of an adrenal m ass as an adenoma can be made with high specificity and acceptable sen sitivity by visually comparing opposed-phase with in-phase GRE images.