Correlation of 18F-FLT uptake with tumor grade and Ki-67 immunohistochemistry in patients with newly diagnosed and recurrent gliomas.

We evaluated 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) uptake in patients with newly diagnosed and recurrent gliomas and correlated the results with tumor grade and proliferative activity. (18)F-FLT PET was investigated retrospectively in 56 patients, including 36 with newly diagnosed gliomas and 20 with recurrent gliomas. The standardized uptake values for tumor and normal contralateral hemisphere were calculated, and the tumor-to-normal (T/N) ratio was determined. Tumor grading and proliferative activity were estimated in tissue specimens. There was a significant difference in T/N ratio among different grades of newly diagnosed gliomas and between low- and high-grade newly diagnosed and recurrent gliomas. (18)F-FLT uptake correlated more strongly with the proliferative activity in newly diagnosed gliomas than in recurrent gliomas. (18)F-FLT PET seems to be useful in the noninvasive assessment of grade and proliferation in gliomas, especially newly diagnosed gliomas.