Usefulness of composite methionine-positron emission tomography/3.0-tesla magnetic resonance imaging to detect the localization and extent of early-stage Cushing adenoma

J Neurosurg. 2010 Apr;112(4):750-5. doi: 10.3171/2009.7.JNS09285.


Object: Fifty to eighty percent of Cushing disease is diagnosed by typical endocrine responses. Recently, the number of diagnoses of Cushing disease without typical Cushing syndrome has been increasing; therefore, improving ways to determine the localization of the adenoma and making an early diagnosis is important. This study was undertaken to determine the present diagnostic accuracy for Cushing microadenoma and to compare the differences in diagnostic accuracy between MR imaging and PET/MR imaging.

Methods: During the past 3 years the authors analyzed the diagnostic accuracy in a series of 35 patients with Cushing adenoma that was verified by surgical pituitary exploration. All 35 cases of Cushing disease, including 20 cases of "overt" and 15 cases of "preclinical" Cushing disease, were studied. Superconductive MR images (1.5 or 3.0 T) and composite images from FDG-PET or methionine (MET)-PET and 3.0-T MR imaging were compared with the localization of adenomas verified by surgery.

Results: The diagnostic accuracy of superconductive MR imaging for detecting the localization of Cushing microadenoma was only 40%. The causes of unsatisfactory results for superconductive MR imaging were false-negative results (10 cases), false-positive results (6 cases), and instances of double pituitary adenomas (3 cases). In contrast, the accuracy of microadenoma localization using MET-PET/3.0-T MR imaging was 100% and that of FDG-PET/3.0-T MR imaging was 73%. Moreover, the adenoma location was better delineated on MET-PET/MR images than on FDG-PET/MR images. There was no significant difference in maximum standard uptake value of adenomas evaluated by MET-PET between preclinical Cushing disease and overt Cushing disease.

Conclusions: Composite MET-PET/3.0-T MR imaging is useful for the improvement of the delineation of Cushing microadenoma and offers high-quality detectability for early-stage Cushing adenoma.

Publication types

  • Clinical Trial
  • Validation Study

MeSH terms

  • ACTH-Secreting Pituitary Adenoma* / diagnostic imaging
  • ACTH-Secreting Pituitary Adenoma* / pathology
  • ACTH-Secreting Pituitary Adenoma* / surgery
  • Adenoma* / diagnostic imaging
  • Adenoma* / pathology
  • Adenoma* / surgery
  • Adolescent
  • Adrenocorticotropic Hormone / blood
  • Adrenocorticotropic Hormone / metabolism
  • Adult
  • Aged
  • Child
  • Early Diagnosis
  • False Negative Reactions
  • False Positive Reactions
  • Female
  • Fluorodeoxyglucose F18
  • Humans
  • Magnetic Resonance Imaging / methods*
  • Magnetic Resonance Imaging / standards
  • Male
  • Methionine
  • Middle Aged
  • Pituitary ACTH Hypersecretion* / diagnostic imaging
  • Pituitary ACTH Hypersecretion* / pathology
  • Pituitary ACTH Hypersecretion* / surgery
  • Positron-Emission Tomography / methods*
  • Positron-Emission Tomography / standards
  • Preoperative Care
  • Reproducibility of Results
  • Young Adult


  • Fluorodeoxyglucose F18
  • Adrenocorticotropic Hormone
  • Methionine