A clinical and histopathological study of factors affecting MRI signal intensities of pituitary adenomas

Neuroradiology. 1994 May;36(4):298-302. doi: 10.1007/BF00593265.


Our aim was to elucidate the factors which determine the MRI signal intensities of pituitary adenomas. We examined 51 patients with surgically-confirmed pituitary adenomas. Using a spin-echo pulse sequence (SE 500/15), coronal and sagittal images (3 mm slices) were obtained. Signal intensities on T1-weighted images were measured in the parenchyma of the adenoma and in normal grey matter. The relative intensity of the adenoma was assessed by calculating the ratio of its signal intensity to that of the normal grey matter of the same patient. Paraffin-embedded sections were used for haematoxylin and eosin staining. The number of cells in a prescribed area was counted, and the mean of five such counts was taken as the cell density. Immunohistochemically stained sections using antibodies for various pituitary hormones were similarly examined; the ratio of the total number of hormone-positive cells to the overall total number of adenoma cells was calculated. Four independent variables were used in the analysis: the age of the patient, the maximum diameter of the adenoma, the cell density and the proportion of hormone-positive cells in the adenoma and, with the signal intensity ratio as the dependent variable, a multiple regression analysis was performed. This revealed that the the greatest influence upon the signal intensities on T1-weighted images was the proportion of hormone positive cells.

MeSH terms

  • Adenoma / diagnosis*
  • Adenoma / pathology
  • Adenoma / surgery
  • Adrenocorticotropic Hormone / metabolism
  • Adult
  • Aged
  • Cell Count
  • Contrast Media
  • Drug Combinations
  • Female
  • Follicle Stimulating Hormone / metabolism
  • Gadolinium DTPA
  • Growth Hormone / metabolism
  • Humans
  • Luteinizing Hormone / metabolism
  • Magnetic Resonance Imaging*
  • Male
  • Meglumine
  • Middle Aged
  • Organometallic Compounds
  • Paraneoplastic Endocrine Syndromes / diagnosis*
  • Paraneoplastic Endocrine Syndromes / pathology
  • Paraneoplastic Endocrine Syndromes / surgery
  • Pentetic Acid / analogs & derivatives
  • Pituitary Gland / pathology
  • Pituitary Neoplasms / diagnosis*
  • Pituitary Neoplasms / pathology
  • Pituitary Neoplasms / surgery
  • Prolactin / metabolism
  • Prolactinoma / diagnosis
  • Prolactinoma / pathology
  • Prolactinoma / surgery
  • Thyrotropin / metabolism


  • Contrast Media
  • Drug Combinations
  • Organometallic Compounds
  • Meglumine
  • Pentetic Acid
  • Adrenocorticotropic Hormone
  • Prolactin
  • Luteinizing Hormone
  • Follicle Stimulating Hormone
  • Thyrotropin
  • Growth Hormone
  • Gadolinium DTPA