Postoperative controls in surgically treated hormonactive pituitary adenomas by use of magnetic resonance imaging.

The search of reliable imaging methods to detect the substrate for persisting hypersecretion in patients operated on for hormonactive pituitary adenoma prompted us to study the possibilities of the newly available Magnetic Resonance Imaging (MRI) technique in this regard. Pre- and postoperative MRI-studies where performed in 5 patients with persisting GH excess following transsphenoidal surgery as well as in 3 patients with micro- and 2 patients with macroprolactinomas. The MRI-findings were correlated with the results of the endocrinological examinations. Two acromegalic patients and three cases with microprolactinomas, who were successfully operated upon as defined by the functional criteria were also included to obtain a baseline for normal postoperative findings. The MRI-study was positive in all of the five patients with persisting GH-overproduction. In prolactinomas, the substrate of hypersecretion could only be detected, when the PRL-value exceeded 2,000 microU/ml. MRI may present an important diagnostic method for evaluating further treatment options in patients with remaining hormonal hypersecretion following transsphenoidal adenomectomy, particularly with regard to a second surgical approach.