Transsphenoidal surgery in acromegaly investigated by intraoperative high-field magnetic resonance imaging.

Objective: The aim of the study was to evaluate the effect of intraoperative high-field (1.5 Tesla) magnetic resonance imaging (MRI) on the results of transsphenoidal surgery of GH-secreting pituitary macroadenomas.

Methods: Twenty-three acromegalic patients (mean tumor size, 25 +/- 12 mm; untreated preoperative GH, 4.