Differentiation of glioblastoma multiforme from astrocytomas by in vitro 1H MRS analysis of human brain tumors

In vitro high resolution ¹H NMR spectroscopy allows non-invasive metabolic evaluation of specimens derived from surgically biopsed or resected brain tumors, with the aim of identifying potential markers of different malignancy grading, and improving diagnostic and therapeutic strategies. In the present study we evaluated 36 patients affected by different brain gliomas (7 well differentiated astrocytomas, 7 anaplastic astrocytomas, 16 glioblastomas, 6 oligodendrogliomas). These analyses allowed discrimination between well differentiated and anaplastic astrocytomas (AII + AA) and glioblastomas multiforme (GM) samples on the basis of the ratio between the integrated choline-containing resonance (b'Cho') and the creatine peaks (creatine (Cr) + Phosphocreatine (PCr)). While no definite difference was found between AII and AA, significantly higher values were observed for this ratio in GM. Other signals, derived from different metabolites, such as Glycine (Gly) and N-acetyl-aspartate (NAA), may also assume relevance in differential tumor diagnosis. In this study an increased [Gly]/[Cr+PCr] ratio was observed in GM with respect to AII and AA. The NAA levels observed in our tumor specimens may be explained on the basis of tumor cell infiltration into brain adjacent tissue. Interesting, but inconclusive, are the data concerning oligodendrogliomas, which, also in well differentiated forms, exhibit increased levels of b'Cho'/(Cr+PCr) ratio. The present study confirms the role of MRS in the biochemical characterization of neoplastic brain tissue and its potential contribution to a better selection of multidisciplinary treatment strategies.