Magnetic resonance imaging characteristics of residual pituitary tissues following transsphenoidal resection of pituitary macroadenomas.

Abstract

The present study is to investigate the pre- and post-operative magnetic resonance imaging of pituitary tissues following transsphenoidal resection of pituitary macroadenomas, as well as its clinical significance. The medical records of 108 consecutive pituitary macroadenoma patients admitted at Fuzhou 900th Hospital between September 2012 and September 2014 were retrospectively reviewed. Siemens 3. 0T magnetic resonance scanner was used to perform pre- and postoperative MRI scanning, including plain scan and contrast-enhanced scan of SE sequential T1WI and T2WI in sagittal, coronal and axial views. PACS medical imaging system was used to measure the diameter of pituitary adenoma, as well as the volumes of the adenoma and pituitary tissue. Hematoxylin-eosin staining and immunohistochemical staining were also performed. Higher height of pituitary adenoma results in lower rate of posterior pituitary bright spot (PPBS) on MR T1-weighted imaging. Preoperative MR signal intensity of PPBS was negatively related to diabetes insipidus (DI). Normal pituitary tissues were likely to be above the pituitary adenomas in growth hormone-secreting adenoma patients, while mostly located aside in gonadotropin-secreting adenoma patients. Morphological restitution of postoperative pituitary tissues was better in lateral displacement than that in superior or superolateral patterns on pre-operative MR images. Positive rate of PPBS on preoperative MRI is negatively related to adenoma height, and the signal intensity of PPBS is inversely related to postoperative DI. The relative locations of pituitary tissues and adenoma tissues may be associated with the adenoma type and may affect the postoperative remodeling of residual pituitary tissues.