[The value of MR tomography after transsphenoidal hypophyseal resection. A retrospective comparison between...

Postoperative magnetic resonance images of 40 patients after transsphenoidal surgery for pituitary adenoma were evaluated retrospectively. The signal intensities of packing material and residual tumour were analysed. T1-weighted spin-echo sequences were obtained in coronal and sagittal views with and without intravenous injection of contrast media. Residual tumour demonstrated homogeneous or inhomogeneous signal intensity on the native scan with homogeneous or inhomogeneous enhancement. Packing material demonstrated a homogeneous signal intensity on the images obtained without injection of contrast media with a peripheral enhancement or alternate layers of low and intermediate signal intensity with alternate enhancement after injection of contrast media. In 5 of 54 examinations different results were found in MRI, endocrinology and surgery (two false negative and one false positive MRI in correlation with endocrinology; two residual tumours on MRI where surgery was supposed to be complete). Application of intravenous contrast media facilitates the interpretation of postoperative examination of the pituitary gland as well as comparison with preoperative examinations and the knowledge of the intraoperative procedure.