C-11methionine positron emission tomography in recurrent gliomas

Objective: In this study we investigate the malignant progression of recurrent gliomas using C11 Methionine Positron Emission Tomography (PET).

Methods: Seventeen Patients with histologically proven glioma were investigated repeatedly with C11-methionine PET. In total 40 C11-methionine PET scans were done. Each patient underwent follow-up C11-methionine PET investigation before open surgery or stereotactic biopsy.

Results: During the study 13 patients had histologically proven progression of tumor grade (in two cases in two steps from grade II to grade III and later to grade IV). Four patients demonstrated no change in tumor grade. In all patients the ratio between C11-methionine uptake in the tumor and in the contralateral cortex was determined.

In patients with malignant progression the mean increase of methionine uptake was 56.2% (±55.5%) and in patients without change in tumor grade there was no change in methionine uptake (7,5%±24.7%). The increase of methionine uptake in the group with malignant progression was significant (p=0.003), whereas change of methionine uptake in the group without malignant progression showed no significance (p=0.421).

Conclusion: We concluded that C11-methionine PET is a useful tool to detect malignant progression in recurrent gliomas even in the progression from grade III to grade IV.