The value of magnetic resonance spectroscopy and diffusion tensor imaging in characterization of gliomas growth patterns and treatment efficiency

The objective of the study was to assess the usefulness of magnetic resonance spectroscopy (MRS) and diffusion tensor imaging (DTI) in detection of vital tumor cell infiltration presence in peritumoral brain areas and determination of biochemical changes in the brain parenchyma after received treatment. 73 patients with present, morphologically conformed brain gliomas and 77 gliomas patients in remission stage after combined therapy underwent magnetic resonance imaging (MRI) including MRS and DTI. Fractional anisotropy (FA) and metabolite ratios—choline/creatine (Cho/Cr), myoinositol/creatine (MI/Cr), lactate-lipid/creatine (LL/Cr), N-acetyl aspartate/creatine (NAA/Cr)—were measured in the tumor, perifocal edema zone, distant and contra-lateral normal appearing white matter. We observed gradual reduction of Cho/Cr, MI/Cr, LL/Cr mean ratios and step-by-step increase of NAA/Cr, FA mean values in the direction from the tumor to the distant and contra-lateral normal-appearing white matter. LL/Cr ratios within distal normal appearing white matter decreased in patients after radiotherapy/chemotherapy. Our study suggests that MRS and DTI in combination with structural MRI sequences enhance vital glial tumor cells areas and possible infiltration border. MRS and DTI quantitative measurements in the glioma peritumoral area reveal pathological changes, despite the normal signal intensity in structural MRI. We suggest that increased LL/Cr ratios and decreased FA values may have the superior implications in the detecting of glial tumors extent along the white matter tracts. NAA/Cr reduction and Cho/Cr increase may provide additional diagnostic value. LL/Cr ratio in distal normal signal intensity area could be used as radiation/chemotherapy effectiveness criteria, as this will reduce after the received treatment and in remission period.