Correlative study of MR perfusion weighted imaging with histopathologic grade in glioma

Objective: Relative cerebral blood volume(rCBV) is a commonly used perfusion MRI technique for the evaluation of glioma grade. Relative cerebral blood flow(rCBF) has less been studied. The goal of our study is to determine the usefulness of two parameters in evaluating the histopathologic grade of glioma. Methods: This study involved 36 patients(23 high-grade and 13 low-grade) who were identified as having histopathologically proven gliomas. MR perfusion imaging and MR conventional imaging were performed preoperatively in them. The perfusion data were deconvoluted to get a color map of CBV and CBF. The maximal rCBV and rCBF ratios of each lesion were calculated and were correlated with histopathologic grading of gliomas. Results: The maximal rCBV and rCBF ratios of high-grade gliomas were statistically different from those of low-grade gliomas(P0.01). There was a strong correlation between the maximal rCBV and rCBF ratios(r=0.812, P0.05). There was frequent mismatch(30%) between the qualitative assessment of the contrast-enhanced T1 weighted MR imaging and the perfusion maps. Conclusion: MR perfusion imaging is useful in the preoperative assessment of the histopathologic grade of gliomas. The maximal rCBF ratio in addition to the maximal rCBV ratio can be incorporated in MR perfusion analysis for the evaluation of cerebral gliomas.