Exploratory clinical investigation of (4S)-4-(3-18FFluoropropyl)-L-glutamate pet of inflammatory and infectious lesions

Abstract

We explored system x? C transporter activity and the detection of inflammatory or infectious lesions using (4S)-4-(3-18F-fluoropropyl)-L-glutamate (18F-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. 18F-FSPG images were assessed visually and quantitatively. Expression levels of xCT, CD44, and surface markers of inflammatory cells were evaluated by immunohistochemistry. Results: 18F-FSPG PET detected all reference lesions. 18F-FSPG uptake in sarcoidosis was significantly higher than that in nonsarcoidosis. The lesion-to-blood-pool SUV ratio for 18F-FSPG was comparable to that for 18F-FDG in sarcoidosis. In nonsarcoidosis, however, it was significantly lower. In 5 patients with available tissue samples, the SUVmax for 18F-FSPG and CD163 were negatively correlated (? 5-0.872, P 5 0.054). Conclusion: 18FFSPG PET may detect inflammatory lesions when activated macrophages or monocytes are present, such as in sarcoidosis.