gms | German Medical Science

Objective: In most cases indication for or against surgery in gliomas is based on MRI ± contrast-enhancement (±CE). FET is an aminoacid-marker with a high specifity for tumor tissue. This study was performed to see whether the additional use of FET-PET influences the decision making for glioma surgery.

Methods: 30 patients were included in this retrospective study between March 2006 and September 2007. Patients were examined with MRI ± CE and FET-PET and were diagnosed primarily for gliomas or were suspicious for tumor recurrence. Original diagnostic films and material and also documented statements were evaluated. The decision pro or contra surgery was influenced by CE in MRI (=MRI+) and/or a significant tracer enrichment in FET-PET (=PET+). The histopathological findings were correlated to the results of both diagnostic tools.

Results: 23 of the 30 patients were suspicious for recurrent gliomas. 15/23 had primarily a low-grade glioma (WHO II). Out of these 15, six patients had no CE in MRI (=MRI-), although PET was positive. We followed the positive PET finding and the recurrent glioma was extirpated. In 3/6 the histopathology showed an upgrading (WHO III), in 3/6 it remained as a low-grade glioma. In 5 of the 15 low-grade tumors both MRI and PET were negative, which enforced us not to operate.

8/23 had primarily high-grade gliomas (WHO III+IV) and 7/8 were MRI+. This finding was established by PET+. In this cases the decision pro surgery was not influenced by PET.

7 out of the 23 patients were primarily diagnosed for glioma. Most of them (n=5) were MRI-, although PET showed a positive finding. PET supported surgery and histopathologically all patients showed a low-grade glioma.

Conclusions: With this study we could show, that especially in recurrent low-grade gliomas FET-PET is a good tool to decide whether to operate or not. It shows an upgrading of gliomas earlier than MRI.