Differentiation of adrenal masses with MR imaging: comparison of techniques.

Abstract

To determine the efficacy of various magnetic resonance (MR) imaging sequences for the differentiation of adrenal masses. Fifty-three adrenal masses in 46 patients (adenomas, metastases, myelolipomas, hemorrhages, and pheochromocytomas) were evaluated by means of T1-, T2-, and T2*-weighted sequences, calculated T2 values, chemical shift imaging techniques, and dynamic contrast material-enhanced imaging. The Student t test and receiver operating characteristic analysis were used to evaluate the differences in the groups of masses. Analysis of the chemical shift-induced signal intensity of the adrenal masses and the T2*-weighted sequence enabled differentiation of adenomas, metastases, and pheochromocytomas. Adenomas and pheochromocytomas were also differentiated by means of a heavily T2-weighted sequence. Signal intensity values for all masses overlapped. Although a chemical shift imaging technique and a T2*-weighted sequence helped correctly differentiate among the groups of adrenal masses, the degree of overlap suggests that it is still difficult to evaluate disease in individual patients.