Normal development of the pituitary gland: assessment with three-dimensional MR volumetry.

BACKGROUND AND PURPOSE Currently available data on pituitary volume have been based on indirect methods of measurement and are mostly limited to adult populations. The purpose of this study was to determine the normal development of pituitary volume by means of direct measurements made on thin-section 3D MR acquisitions. METHODS The volume of the normal pituitary gland in children and adolescents was measured by using 3D MR sequences with a section thickness of 0.6 to 0.75 mm. The clinical study group consisted of 199 pediatric patients with clinically normal pituitary function and no abnormal findings on routine MR studies. The volume of the posterior pituitary was also measured in all the subjects. RESULTS A phantom study revealed measurement errors within 25%. In the clinical study, the measured pituitary volumes showed a growth spurt during puberty, which was more prominent in girls. Posterior pituitary volumes showed gradual growth without such a spurt. Among 5- to 9-year-olds, the posterior pituitary volumes were significantly larger for boys than for girls. CONCLUSION Normal development of the pituitary gland and posterior pituitary was determined by means of 3D MR volumetry. With this technique, we found a gender difference in the volume of the posterior pituitary.