Imaging of adrenal masses.

Most adrenal masses are detected on CT scans, but only a minority has morphologic features that are characteristic of a specific histologic diagnosis. In patients with clinical or biochemical features of a hyperfunctioning adrenal syndrome, CT detection of a unilateral adrenal mass typically leads to surgical resection, although functional assessment of the mass with iodomethylnorcholesterol or MIBG scintigraphy sometimes is used to augment the CT findings. In patients with a nonhyperfunctioning adrenal mass, chemical shift MR and CT densitometry have begun to replace percutaneous adrenal biopsy or serial follow-up CT as methods to establish a specific diagnosis. In this article the authors review the clinical features and imaging findings of patients with known or suspected adrenal masses.