Аннотация:Glioblastoma (GBM) is a heterogeneous tumor entity. Forty-eight biopsy specimens [23 belonging to contrast-enhancing (CE) and 25 belonging to non-contrast enhancing (NE) regions] from 12 patients with newly diagnosed GBM were removed by a frameless image-guided stereotactic biopsy technique followed by tumor resection. Variables of conventional and advanced magnetic resonance imaging (MRI) and 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) (18F-FDG) positron emission tomography (PET) from each biopsy site were recorded. They were then compared with histopathologic and molecular features, and with stemness potential, as assessed by in vitro culture.
Biopsy specimens from the CE ring showed the highest values of 18F-FDG maximum standardized uptake (SUVmax) on PET, relative cerebral blood volume (rCBV), Choline/Creatine (Cho/Cr), Choline /N-acetylaspartate (Cho/NAA) and Lipids/Lactate (LL) ratio. They corresponded to the most malignant tumor phenotype, to the greatest molecular spectrum and to GBM stem cell (GSC) potential.
In CE areas, apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were very variable.
18F-FDG SUVmax on PET, rCBV and Cho/Cr ratio resulted the most suitable parameters to detect tumor infiltration. In edematous areas, reactive astrocytes and microglia/macrophages are the influencing variables.
Combined MRI and 18F-FDG PET allowed to recognize the specific biological significance of the different identified areas.