MR findings before and after transsphenoidal surgery were evaluated in 6 cases. T1-weighted (TR/TE 600/20) sagittal and coronal images with 2 or 4 acquisitions were obtained, using 3-mm slice thickness and 0.3-mm interslice gaps. Of 18 MR examinations, 13 included coronal i.v. contrast medium enhanced images. Image quality, sinus cavernosus invasion, identification of normal pituitary tissue and tumor size were examined. All MR studies clearly demonstrated the macroadenomas whether 2 or 4 acquisitions were used, and whether i.v. contrast medium was administered or not. Surgically confirmed sinus cavernosus infiltration was seen in 4 patients. The pituitary stalk was identified separate from the tumor in 2 patients, and the gland in one. There was reduction in tumor size over time, indicating that final radiologic assessment after transphenoidal surgery is best performed 4 to 6 months postoperatively. It should not be necessary to routinely include i.v. contrast medium injection in the postoperative evaluation of macroadenomas.