ROLE OF MAGNETIC-RESONANCE-IMAGING IN HYPOTHALAMIC-PITUITARY DISORDERS

Improvement of MRI diagnostic accuracy in the study of the hypothalami c-pituitary region provides precise anatomic details. In pituitary dwa rfism, MRI reveals severe sella/pituitary gland and stalk hypoplasia w ith or without posterior pituitary ectopia, and empty sella, and this more frequently in patients with multiple pituitary hormone deficiency . Two main hypotheses have been proposed to explain these findings: tr aumatic stalk transection during breech delivery, and abnormal embryon ic development of the pituitary gland. The association between neurora diological findings and type/severity of endocrine alteration has not yet been clarified. In diabetes insipidus, MRI findings are normal pic ture, posterior lobe not visible, and thickened stalk (as expression o f preclinical/initial histocytosis). Patients with central precocious puberty or hypogonadotropic hypogonadism rarely show morphologic abnor malities (hamartoma of the tuber cinereum, partially empty sella). So far, MRI permits one to identify morphologic pictures in diseases prev iously considered 'idiopathic'.