Morphological changes on MR imaging of the normal pituitary gland related to age and sex: main emphasis on pubescent females.

The pituitary gland of 300 individuals (ages: 3-85 years; 101 males and 199 females) with no pituitary gland related symptoms were studied using a 1.5-T superconductive magnetic resonance imaging (MRI) unit. The focus of the study was on morphological changes at puberty in females. Among three parameters related to pituitary size, height changed the most remarkably in relation to age and sex, reaching a peak towards the first half of the third decade of a women's life. However, the convex shaped upper pituitary surface was most often recognized in the first half of the second decade. Moreover, in children and adolescents, this shape was predominantly shown by females. A coronal deviation of the stalk attachment to the pituitary gland, which might be indicative of pituitary tumour, was most frequently observed in individuals less than 20 years of age and those over 50. The pituitary size and shape varied, especially with respect to height, likely in response to changes in the hormonal environment. Hence, care must be taken when evaluating the size of the pituitary gland by MRI, especially in the diagnosis of pituitary tumour.