Exploratory Clinical Investigation of (4S)-4-(3-18F-Fluoropropyl)-L-Glutamate PET of Inflammatory and Infectious Lesions

J Nucl Med. 2016 Jan;57(1):67-9. doi: 10.2967/jnumed.115.164020. Epub 2015 Oct 15.


We explored system [Formula: see text] transporter activity and the detection of inflammatory or infectious lesions using (4S)-4-(3-(18)F-fluoropropyl)-l-glutamate ((18)F-FSPG) PET.

Methods: In 10 patients with various inflammatory or infectious diseases, as many as 5 of the largest lesions were selected as reference lesions. (18)F-FSPG images were assessed visually and quantitatively. Expression levels of xCT, CD44, and surface markers of inflammatory cells were evaluated by immunohistochemistry.

Results: (18)F-FSPG PET detected all reference lesions. (18)F-FSPG uptake in sarcoidosis was significantly higher than that in nonsarcoidosis. The lesion-to-blood-pool SUV ratio for (18)F-FSPG was comparable to that for (18)F-FDG in sarcoidosis. In nonsarcoidosis, however, it was significantly lower. In 5 patients with available tissue samples, the SUVmax for (18)F-FSPG and CD163 were negatively correlated (ρ = -0.872, P = 0.054).

Conclusion: (18)F-FSPG PET may detect inflammatory lesions when activated macrophages or monocytes are present, such as in sarcoidosis.

Keywords: glutamate; infection; inflammation; positron emission tomography; xC− transporter.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Glutamates* / metabolism
  • Glutamates* / pharmacokinetics
  • Humans
  • Infections / diagnostic imaging*
  • Infections / metabolism
  • Male
  • Middle Aged
  • Positron-Emission Tomography / methods*
  • Sarcoidosis / diagnostic imaging
  • Sarcoidosis / metabolism
  • Tissue Distribution
  • Tomography, X-Ray Computed


  • (4S)-4-(3-(18F)fluoropropyl)-L-glutamate
  • Glutamates