Objective: To determine the diagnostic accuracy of pre operative Perfusion Magnetic Resonance Image Grading and its correlation with post operative Histopathological Grading of Primary Intra Axial Gliomas. Materials and Methods: In order to determine relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), 30 patients with glioma underwent dynamic contrast enhanced T2 weighted and conventional T1 and T2 weighted imaging. rCBV and rCBF maps were obtained by fitting a gamma –variate function to the contrast material versus time curve. rCBV, rCBF ratios between tumor and corresponding area of normal side (maximum rCBV/ rCBF of tumor and rCBV/rCBF of contralateral white matter) were calculated and compared between glioblastomas (grade IV), anaplastic gliomas (grade III) and low grade gliomas (grade I & II). The grading obtained by the perfusion MR images was compared with the post operative histopathological grading. Results: Mean rCBV & rCBF ratios were 10.53±2.73 & 9.30±1.10 for glioblastomas (grade IV), 7.55±1.35 & 6.96±0.88 for anaplastic gliomas (grade III), 4.72±0.92 & 4.54±0.54 for diffuse astrocytomas and oligodendrogliomas (grade II), 1.84±0.94 & 1.59±0.79 for low grade gliomas (grade I), and were thus significantly different; p< 0.03 between glioblastomas and anaplastic gliomas, p< 0.02 between anaplastic gliomas and diffsuse astrocytomas, oligodendrogliomas, p< 0.003 between grade II and low grade gliomas, p<0.01 between glioblastomas and lowgrade gliomas. Stastistically significant correlation was seen by applying Chi­ square test (p <0.0001). Further the correlation of perfusion MR grading and Histopathological grading was proven by applying Speraman’s correlation value (p <0.0001). Conclusion: Perfusion MR imaging is a useful and reliable technique for estimating the histological grading of primary intra axial gliomas. 

Keywords: Perfusion Magnetic Resonance Imaging; Relative Cerebral Blood Volume; Primary Intra Axial Glioma.