Spectroscopic Characterization of Gliosarcomas-Do They Differ From Glioblastomas and Metastases?

OBJECTIVE: To evaluate the spectroscopic pattern of gliosarcomas for differentiation from glioblastomas or metastases.

METHODS: H-nuclear magnetic resonance (NMR) spectroscopic intermediate echo time data of 5 patients with histologically proven gliosarcomas were compared with data of 17 metastases and 54 glioblastomas. Specialized H-NMR spectroscopy analysis software was used offline. Lipid and macromolecular resonances between 0.9 ppm and 1.4 ppm were compared besides the main metabolites using the Mann-Whitney U test.

RESULTS: Gliosarcomas showed higher lipid and macromolecule resonances and a higher lipid-choline ratio compared with glioblastomas (P < 0.024 and P < 0.036). Glioblastomas showed higher creatine concentrations compared with metastases (P < 0.007) but not compared with gliosarcomas. We found no significant differences between metastases and gliosarcomas.

CONCLUSIONS: Gliosarcomas may mimic metastases on H NMR spectroscopy showing high signal intensities from lipid and macromolecule resonances. This tumor type should be suspected if conventional imaging suggests an intra-axial brain neoplasm in combination with high lipids in solid tumor parts.