摘要
Objectives: The purpose of the present study was to determine whether PET with
11C-methionine (MET) is valuable in distinguishing recurrent tumor from radiation necrosis.
Methods: Twenty-one patients (27 lesions) with previously treated 10 primary or 11 metastatic brain tumor who presented focally enhanced mass lesion on postcontrast magnetic resonance imaging (MRI) images were studied with MET-PET. Uptake of MET was visually interpreted by three independent nuclear medicine physicians in a blind manner. In addition, semiquantitative evaluation was performed in forms of tumor-to-contralateral (TCR) tissue ratio of standardized uptake value (SUV). Final confirmation was established based on pathological diagnosis in 13 lesions and clinical follow-up for more than 6 months in the remaining 14.
Results: Final diagnosis was radiation necrosis in nine lesions and recurrent tumor in 18. Every recurrent tumor showed intense MET uptake while none of the radiation necrosis showed significant MET uptake. Sensitivity as well as specificity of visual interpretation of MET-PET images were 100%. The difference in the mean value of TCR was statistically significant between radiation necrosis and recurrent tumor (1.05±0.11 vs. 1.79±0.32,
p<0.0001).
Conclusions: MET-PET accurately distinguishes recurrent brain tumor from radiation necrosis.