[Magnetic resonance techniques used in the differentiation of adrenal tumors]

Noninvasive differentiation of adrenal masses by imaging studies as computed tomography and magnetic resonance imaging is an accepted diagnostic procedure in patients with extraadrenal neoplasm and discovered on imaging studies adrenal mass or in patients with incidentally discovered adrenal mass. Significant impact on possibilities of differentiation of adrenal masses with magnetic resonance imaging was due to introduction to adrenal imaging such techniques as chemical shift imaging and dynamic imaging with paramagnetic contrast agent. Differentiation of adrenal masses with magnetic resonance imaging involves following parameters: tumor diameter, signal intensity of adrenal mass on T2 weighted images, lipid contents in adrenal tumor evaluated with chemical shift imaging and washout of paramagnetic contrast agent from adrenal mass evaluated with dynamic examination. The best results, reaching 100% sensitivity and 100% specificity in differentiation adrenal adenomas from non-adenomas, can be achieved by combined analysis of all mentioned parameters. In regard to availability and costs computed tomography not magnetic resonance imaging is the examination of choice in visualization of adrenal glands and their pathology and in differentiation of adrenal masses. Adrenal tumors on non-enhanced images with density below 0 Hounsfield units can reliably be diagnosed as adenomas, whereas adrenal tumors with density above 20 Hounsfield units can reliably be diagnosed as non-adenomas. Tumors with density in 0-20 Hounsfield range are ambiguous in character, that in many cases can be determined in magnetic resonance imaging.