Advances in diagnostic techniques of pituitary tumors and prolactinomas.

The main advances in the diagnostic evaluation of pituitary tumors and prolactinomas have been in the areas of improved magnetic resonance techniques and in the use of inferior petrosal sinus sampling. New dynamic techniques of rapid acquisition magnetic resonance imaging during bolus contrast infusion have improved the sensitivity for the diagnosis of the small microadenoma. The development of three-dimensional volume imaging has also led to a further improvement in sensitivity to small lesions of the sella. The measurement of adrenocorticotropin levels in the inferior petrosal sinus in patients with Cushing's syndrome assists in the differentiation of adrenocorticotropin-secreting pituitary tumor from other peripheral causes of the syndrome. The use of corticotropin-releasing hormone concomitant with sampling has proven to be of value in improving sensitivity and specificity. Elevated levels of growth hormone in petrosal sinus sampling have also been shown to be valuable in the early diagnosis of acromegaly when peripheral hormone levels and imaging are nondiagnostic.