[The comparison of the external and internal standards using 1HMRS method in diagnostics of brain tumours]

The aim of the study was the comparison of usefulness of the external and internal standards using 1HMRS method in diagnostics of brain tumors. The study was performed using MRI Signa Excite 1.5T system with SVS and PRESS technique (TR=1500ms, TE=35ms) and covered 100 patients with brain tumors (low and high grade of malignancy). The concentration of metabolites from voxels located in contralateral unchanged cerebral tissue was analyzed. Additionally 30 healthy volunteers were examined (the external model). Comparison of external and internal models showed lack of statistically considerable differences for all analyzed metabolites except the mi concentration. In case of Cho, Cr, Lac, Lip, GIx concentration, it was noticed that in group of patients with brain tumors mean values were slightly (insignificantly) increased in comparison to external model. In case of NAA concentration, an opposite relation was stated. Comparing group of patients with high grade of malignancy, to patients with low grade of malignancy slightly increased values of all metabolites was observed. In group of patients with high grade of malignancy, statistically significant high ml concentration was observed compared to patients with low grade of malignancy. In group of patients with low grade of malignancy, statistically significant low mean values of ml concentration was observed, compared to external control group. As referential values it is possible to use results of all analyzed metabolites (NAA, Cho, Cr, Lip, Lac, Ala, GIx) except ml interchangeably for the external and internal standards.