To assess pituitary vascularization in children with hypopituitarism, central diabetes insipidus (DI), or Langerhans cell histiocytosis.Dynamic MR images were obtained through the pituitary stalk after injection of gadopentetate dimeglumine in 21 patients (11 boys and 10 girls, aged 4-17 years) and 10 age-matched control subjects.Initial enhancement of the posterior pituitary lobe occurred simultaneously with that of the straight sinus in all subjects except four patients with central DI and a thick stalk. Enhancement of the entire anterior pituitary lobe was statistically significantly prolonged (P < .005) in the four patients with delayed initial posterior pituitary lobe enhancement.Fast-framing dynamic MR imaging provides new information...