Magnetic resonance imaging of the adrenal lesions

Magnetic resonance imaging (MRI) was performed in 18 patients with adrenal masses using a superconducting magnet operating at 1.5 Tesla. Seven pheochromocytomas, five aldosterone-producing adenomas, two hydrocortisone-producing adenomas, two adrenal metastases, one adrenal carcinoma and one adrenal myelolipoma were examined by this method. Spin-echo pulse sequences were obtained at the repetition time (TR) 0.1 ∼ 1.6 sec and the echo time (TE) 14 ∼ 75 msec. T1-weighted images of phechromocytomas were similar in signal intensity to the kidney, while T2-weighted images revealed much higher intensity than those of the liver and kidney. The signal intensity on T1-and T2-weighted images of adrenal adenomas were similar, irrespective of endocrine characteristics, to that of the liver and kidney. T1-weighted images which detect small masses more than 1 cm in diameter offer anatomic resolution similar to computed tomography (CT) and T2-weighted images give information about internal characteristic of adrenal masses. It is expected that MRI is more useful in diagnosis of adrenal masses than CT. (author)