Discriminatory power of MRI for differentiation of adrenal non-adenomas vsadenomas evaluated by means of ROC analysis: Can biopsy be obviated?

The purpose of our study was to evaluate the discriminatory power of MRI in high-field magnet (1.5 T) for differentiation of adrenal non-adenomas vs a denomas assessing the following parameters separately and in combination: m ean diameter of adrenal mass; previously described and new ratios as well a s index calculated from signal intensity (SI) on SE T2-weighted images, che mical shift imaging and Gd-DTPA-enhanced dynamic studies. hundred eight adr enal masses (36 non-hyper-functioning adenomas, 27 pheochromocytomas, 23 al dosterone-secreting adenomas, 20 malignant mass;and 2 cortisol-secreting ad enomas) in 95 patients ere evaluated with SE sequences, CSI and Gd-DTPA dyn amic studies. Indices and ratios of SI for all examined MRI methods were ca lculated and examined retrospectively for significance of differences the g roups with calculation of sensitivity and specificity. Receiver operating c haracteristics (ROC) analysis of calculated parameters in combination was p erformed. The multifactorial analysis of all our parameters, including size of the tumor, T2(liver) index. CSI ratio reflecting lipid content in the t umor I Wo(max/last) ratio reflecting maximal washout of contrast agent from the tumor had 100 % sensitivity and 100 % specificity in characterization of adrenal non-adenoma. The best performance of combination of mean tumor d iameter with single MRI SI parameter ter was achieved in combination with T 2(liver) index for all adrenal masses (area under ROC 0.987) and CST ratio for non-hyperfunctioning adrenal masses (area under ROC 0.991). Magnetic re sonance imaging enables sensitive and specific diagnosis of adrenal non-ade noma.