Utility of magnetic resonance in the etiologic diagnosis of hypopituitarism

The diagnosis of hypothalamic-pituitary disorders relies on a combination of clinical and biochemical data and imaging techniques. During the last decade, computed tomography (CT) has been the best technique for the evaluation of the hypothalamuspituitary region, but in recent years magnetic resonance (MR) has improved the diagnostic efficiency of CT. We retrospectively review the clinical records of 40 hypopituitary patients from the endocrinology unit of our hospital. The aim of the present study was to establish the role of MR in the etiologic diagnosis and anatomic definition of hypopituitarism, when compared with CT. Secondarily, we studied the different pituitary hormones in this condition. The diagnoses were: 12 postsurgical hypopituitarism, 10 empty sella turcica, 7 Sheehan's syndrome, 5 idiopathic hypopituitarism, 3 pituitary disgenesis, 2 craniopharyngioma and 1 macroprolactinoma. GH was the most commonly affected hormone, followed by gonadotrophins, corticotrophin and thyrotrophin (100%, 94%, 76% and 68% respectively). In 24 patients both MR and CT studies were performed. MR was diagnostic in 22 patients, and CT in 15 patients (p < 0.05). MR offered improved diagnostic or anatomical data in 16 patients of the 24 in whom both techniques were performed (p < 0.05). We conclude that MR allows a better definition of the hypothalamus-pituitary region than CT, contributing to the etiologic diagnosis and improving the anatomical findings. Empty sella turcica should be considered a common cause of hypopituitarism.