Purpose. The study of plastic and energy metabolism and their correlation with various histologic types of brain gliomas. Assessment of heterogeneity tumor structure and adjacent brain tissues by comparing MRI and 11C-methionine and 18F-fluorodeoxyglucose PET/CT data.

Materials and methods. 52 patients (M/F 27/25, average age 48±12 years) with gliomas were enrolled in this study: glioblastoma (n = 19), anaplastic astrocytoma (n=9), diffuse astrocytoma (n=9), anaplastic oligodendroglioma (n=6), oligodendroglioma (n=6). Research protocol consisted from MRI before (T2, T2-FLAIR, 3DT1 (FSPGR) and after contrast enhancement (2DT1 (SE)) and dynamic MET and FDG PET/CT.

Quantification parameters were:  tumor to normal index (T/N) at last 10 min of time-activity curve (reflects the activity of metabolic processes), T/N in first peak of maximum uptake (Pmax) during first 60sec of study (reflects delivery level of radiopharmaceutical agent). Measurements were made in three areas: 1 – tumor core, 2 – edema/infiltration, 3 – intact brain tissue in close vicinity to the tumor borders (outside the T2-FLAIR hyperintensity zone). Сomparison was made between areas 1 and 2, 2and 3, and with intact brain tissue reference; MET and FDG accumulation correlations were studied.

Results. Significant differences in T/N MET between areas 1 and 2 were obtained in all gliomas (p <0.05). Pmax MET differed only in glioblastomas (p <0.0001) and oligodendrogliomas (p <0.05), which correlated with the high level of vascularization of these tumor types. T/N FDG significantly differed between area 2 and 3 (p <0.05), which might allow to evaluate the boundaries of infiltrative growth of glioma, with mandatory comparison with MRI. Strong stable correlations of plastic and energy metabolism (as well as high level of radiopharmaceutical agent delivery) in the core of astrocytomas (Grade II-III) (Rs 0.8, p <0.05) and edema/infiltration area around of glioblastomas (Rs 0.5, p = 0, 02) were found and proved the evolutionary theory of glioma growth.

Conclusion. The patterns of MET/FDG distribution as well as plastic and energy metabolism correlations in different tumor areas (core and edema/infiltration) and intact brain tissue in close vicinity to the tumor borders bring us closer to understanding the fundamental metabolic processes of brain gliomas.