High grade gliomas: The role of dynamic contrast-enhanced susceptibility-weighted perfusion MRI and proton MR spectroscopic imaging in differentiating grade III from grade IV

Background: Advanced MR imaging techniques provide physiologic information which complements the conventional MRI findings. Purpose: To evaluate the role of dynamic contrast-enhanced perfusion MRI and proton MR spectroscopy (MRS) in differentiating grade-III from grade-IV glioma. Results: 40 patients with preliminary diagnosis of glioma according to the conventional MRI study and the WHO classification and grading of glioma underwent dynamic MRI study which revealed, 19 patients (47.5%) are diagnosed as grade-III, and 21 cases (52.5%) are diagnosed as grade-IV. The tumor core relative cerebral blood volume (rCBV) was highly significant (P = 0.000) in differentiating grade III from grade IV with cutoff value of 6,sensitivity of 90.5%, specificity of 68.4%, PVP of 76% and NPV of 86.7%. In proton MR spectroscopy, (CHo/Cr) ratio was significant in differentiating grade III from grade IV glioma (P = 0.02), while CHo/NAA, NAA/Cr and MI/Cr ratios were not significant. Conclusion: The rCBV estimation and the metabolite ratios separately or in combination increase the sensitivity of grading of glioma rather than the conventional MRI