MRI of pituitary adenomas: the position of the normal pituitary gland.

The position of the normal pituitary gland, assessed using gadolinium - enhanced MRI was compared with the position found at surgery for pituitary adenoma in 25 patients. The tumours were five microadenomas and 20 macroadenomas. Using T1-weighted imaging, the anterior lobe could be differentiated on the sagittal image in five patients (20%) and on the coronal image in four (16%). The high intensity of the posterior lobe could be differentiated using T1-weighted sagittal imaging in 13 patients (52%). The normal pituitary gland, which enhanced more strongly than tumour, could be differentiated using Gd-DTPA-enhanced MRI on the sagittal images in 22 cases (88%) and on the coronal image in 17 (68%). In seven patients, the normal pituitary gland surrounded the tumour; it was displaced superiorly in 14 cases and superioposterorly in two but in no case was it displaced anteriorly or downwards.