efficacy of 1h-mrsi and dwi for non-invasive grading of brain gliomas

Background: distinguishing low-grade from high-grade gliomas can aid in optimal treatment planning and prognostication. diffusion-weighted imaging (dwi) and magnetic resonance spectroscopy (mrs) have been applied in several studies for non- invasive glioma grading. however, these studies focused on limited aspects of these imaging techniques and used different study setups, resulting in occasionally inconsistent and incomparable conclusions in the literature. objectives: this study was designed to introduce the optimal imaging setup and the most reliable and applicable imaging parameters in glioma grading, using dwi and mrs. patients and methods: during this prospective study, using a 3t-mr scanner, 55 glioma patients underwent brain mrs with short, intermediate, and long echo times (tes), as well as dwi using low, intermediate, and high b-values. postoperatively, all of the specimens were graded pathologically using light microscopy. results: we found that max (chol/cr)/ min (naa/cr) ((maximum choline to creatine ratio)/(minimum n-acetyl aspartate to creatine ratio)), followed by max (chol/ cr), both in long-te, were the most reliable metabolite ratios on mrs for accurate glioma grading. these had values for area under the curve (auc) of 0.92 (p < 0.05) and 0.89 (p = 0.001), respectively, compared to conventional mr imaging (cmri), which had an auc of 0.83 (p < 0.05). dwi at maximal accuracy showed an auc of 0.80 (p < 0.05). conclusion: max (chol/cr)/min (naa/cr) in long-te was the most reliable of all of the mrs parameters studied, while dwi showed no superiority over cmri in glioma grading. no significant differences existed among the various b-values applied, or between the minimum and mean tumor apparent diffusion coefficient values used in dwi-based glioma grading.