Pituitary magnetic resonance imaging in Cushing's disease

Adrenocorticotropin-secreting pituitary tumor represents about 10 % of pituitary adenomas and at the time of diagnosis most of them are microadenomas. Transsphe- noidal surgery is the first-line treatment of Cushing’s dis- ease and accurate localization of the tumor within the gland is essential for selectively removing the lesion and preser- ving normal pituitary function. Magnetic resonance imaging is the best imaging modality for the detection of pituitary tumors, but adrenocorticotropin-secreting pituitary micro- adenomas are not correctly identified in 30–50 % of cases, because of their size, location, and enhancing character- istics. Several recent studies were performed with the purpose of better localizing the adrenocorticotropin- secreting microadenomas through the use in magnetic resonance imaging of specific sequences, reduced contrast medium dose and high-field technology. Therefore, an improved imaging technique for pituitary disease is man- datory in the suspect of Cushing’s disease. The aims of this paper are to present an overview of pituitary magnetic resonance imaging in the diagnosis of Cushing’s disease and to provide a magnetic resonance imaging protocol to be followed in case of suspicion adrenocorticotropin-secreting pituitary adenoma.