Multimodal metabolic imaging of cerebral gliomas: positron emission tomography with [18F]fluoroethyl-L-tyrosine and magnetic resonance spectroscopy

J Neurosurg. 2005 Feb;102(2):318-27. doi: 10.3171/jns.2005.102.2.0318.


Object: The purpose of this study was to determine the predictive value of [18F]fluoroethyl-L-tyrosine (FET)-positron emission tomography (PET) and magnetic resonance (MR) spectroscopy for tumor diagnosis in patients with suspected gliomas.

Methods: Both FET-PET and MR spectroscopy analyses were performed in 50 consecutive patients with newly diagnosed intracerebral lesions supposed to be diffuse gliomas on contrast-enhanced MR imaging. Lesion/brain ratios of FET uptake greater than 1.6 were considered positive, that is, indicative of tumor. Results of MR spectroscopy were considered positive when N-acetylaspartate (NAA) was decreased in conjunction with an absolute increase of choline (Cho) and an NAA/Cho ratio of 0.7 or less. An FET lesion/brain ratio, an NAA/Cho ratio, and signal abnormalities on MR images were compared with histological findings in neuronavigated biopsy specimens. The FET lesion/brain ratio and the NAA/Cho ratio were identified as significant independent predictors for the histological identification of tumor tissue. The accuracy in distinguishing neoplastic from nonneoplastic tissue could be increased from 68% with the use of MR imaging alone to 97% with MR imaging in conjunction with FET-PET and MR spectroscopy. Sensitivity and specificity for tumor detection were 100 and 81% for MR spectroscopy and 88 and 88% for FET-PET, respectively. Results of histological studies did not reveal tumor tissue in any of the lesions that were negative on FET-PET and MR spectroscopy. In contrast, a tumor diagnosis was made in 97% of the lesions that were positive with both methods.

Conclusions: In patients with intracerebral lesions supposed to be diffuse gliomas on MR imaging, FET-PET and MR spectroscopy analyses markedly improved the diagnostic efficacy of targeted biopsies.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aspartic Acid / analogs & derivatives*
  • Aspartic Acid / metabolism
  • Biopsy
  • Brain / pathology
  • Brain / physiopathology
  • Brain Neoplasms / diagnosis*
  • Brain Neoplasms / pathology
  • Brain Neoplasms / physiopathology
  • Child
  • Child, Preschool
  • Choline / metabolism
  • Energy Metabolism / physiology*
  • Female
  • Fluorine Radioisotopes*
  • Glioma / diagnosis*
  • Glioma / pathology
  • Glioma / physiopathology
  • Humans
  • Image Processing, Computer-Assisted*
  • Magnetic Resonance Imaging*
  • Magnetic Resonance Spectroscopy*
  • Male
  • Middle Aged
  • Neuronavigation
  • Positron-Emission Tomography*
  • Prospective Studies
  • Radiopharmaceuticals*
  • Sensitivity and Specificity
  • Tyrosine / analogs & derivatives*


  • Fluorine Radioisotopes
  • O-(2-fluoroethyl)tyrosine
  • Radiopharmaceuticals
  • Aspartic Acid
  • Tyrosine
  • N-acetylaspartate
  • Choline