Current concepts of imaging in patients with pituitary/hypothalamic dysfunction.

MRI has value in differentiating the normal anatomy and abnormalities of the hypothalamic and pituitary regions. The hypothalamus and the pituitary gland are contiguous structures. They are functionally and physiologically inseparable. The hypothalamus functions primarily as an integrating mechanism for various autonomic and neuroendocrine activities, including temperature regulation, water balance, behavior, and appetite. The adenohypophysis of the pituitary gland contains at least five histologically distinct cell types responsible for hormonal secretion. The characteristic locations of these functional cell types correlate well with the common sites of various pituitary adenomas. MRI can visualize the pituitary gland and the hypothalamus noninvasively in healthy people and in patients with diverse diseases.