Purpose. Comparison of the capabilities of proton 3D MR spectroscopy and PET-CT with ¹¹С -methionine in the diagnosis of glial brain tumors.

Materials and methods. 11 patients aged 32 to 69 years with glial brain tumors of various degrees of malignancy were studied. MR spectroscopy was carried out on a magnetic resonance tomograph with a magnetic field strength of 3.0T. Post-processing of images was carried out in the ReadyView program with the construction of spectra and maps of metabolites. PET-CT examination with 1¹С -MET was performed on a Siemens Biograph 40 True Point PET-CT. The PMOD software was used to analyze the obtained images. In this work, the indices of the Cho/NAA metabolite ratios in tumor tissue were calculated, and the index of ¹¹С -methionine accumulation in the tumor was analyzed. A comparison of parametric maps of the distribution of Cho/NAA and ¹¹С -methionine in the tumor structure was carried out using an originally developed algorithm for combining images obtained on the basis of different modalities.

Results. In most cases (n = 9), there was a coincidence of areas of maximum concentration of metabolites (Cho/NAA) and the most active zones of accumulation of ¹¹С-methionine both on individual anatomical sections and throughout the entire volume of the tumor structure. In two studies coincidences between the location of zones with high metabolic activity according to the data of MRS and PET-CT were not found. A significant correlation between the Cho/NAA and index of ¹¹С-methionine accumulation in high-grade gliomas was found.

Conclusion. 3D MR spectroscopy and PET-CT with ¹¹С-methionine demonstrate the ability to visualize the zones of pathological metabolism in tumor tissue. The accumulation of ¹¹С- methionine and the distribution of the Cho / NAA have a similar pattern of anatomical, including 3D, distribution in gliomas of various degrees of anaplasia.