Purpose: To assess the potential role of chemical shift and dynamic gadolinium-enhanced magnetic resonance (MR) imaging in the characterization of adrenal masses.
Materials and methods: Fifty-one adrenal masses (35 adenomas and 16 nonadenomas) in 43 patients were evaluated with chemical shift MR imaging, dynamic gadolinium-enhanced MR imaging, or both. The relative change in the signal intensity (SI) ratio of the adrenal mass to liver and paraspinal muscles was quantitatively and qualitatively assessed. Opposed-phase gradient-echo (GRE) images were compared 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%). Quantitative ratios corresponding to 100% specificity were also observed, with similar sensitivities. Adenomas could not be differentiated from nonadenomas with visual assessment of maximum SI after contrast material administration or washout.
Conclusion: Characterization of an adrenal mass as an adenoma can be made with high specificity and acceptable sensitivity by visually comparing opposed-phase with in-phase GRE images.